Considering that the kings of Aragon had good relations with England, I've chosen England. So, here is the set of events if FRA doesn't exist, with a cession of Roussillon to ENG:
Code:
[color=white]
###
### Alternative civil war if FRA doesn't exist
### Possible cession of Roussillon to ENG
###
### Carles de Viana
event = {
id = 171451
trigger = {NOT = {exists = FRA}}
random = no
country = ARG
name = "The prince Carles de Viana"
desc = "With the new king Joan II (John II in english), the
confrontation between the king and the oligarchy went on,
reaching new heights. Carles de Viana was the son of the king
Joan II. By 1450 there had already been various problems
between father and son, which led the king, in 1456, to
dispossess his son of his inheritance. But Carles won some
support in Sicily and among the members of the Parliament, and
the king imprisoned him in Barcelona in 1460. The Corts held in
Lleida in the same year, dominated by the oligarchy, who
opposed the king and supported the prince Carles, entrusted the
Generalitat (permanent delegation of the Corts) the raising of an
army in order to eventually fight the king in case he didn't accept
their reivindications."
style = 1
date = {day = 1 month = june year = 1460}
offset = 90
deathdate = {day = 1 month = september year = 1461}
action_a = {name = "Let's free the prince and accept the conditions of the Corts"
command = {type = domestic which = aristocracy value = 1}
command = {type = domestic which = serfdom value = 1}
command = {type = stability value = -2}
command = {type = treasury value = -150}
}
action_b = {name = "We'll never give up !"
command = {type = sleepevent which = 171452}
command = {type = trigger which = 171453}
}
}
### Juana Enríquez
event = {
id = 171452
trigger = {NOT = {exists = FRA}}
random = no
country = ARG
name = "Juana Enríquez and the Civil War"
desc = "After the death of the prince Carles de Viana, who
supported the Corts and the oligarchy, the post of 'lieutenant of
the king' went to the king's wife, Juana Enríquez, a faithful
supporter of the royalist cause. The relation with the Corts
became more difficult than ever as the queen worked hard to
restablish royalist power. The Corts and the Generalitat, afraid of
possible reprisals against them for the previous events, began a
persecution of royalist supporters and raised an army, with which
they besieged the city of Girona, where the queen and her son
were at that very moment. The war seemed inevitable."
style = 1
date = {day = 1 month = march year = 1462}
offset = 210
action_a = {name = "If they want a war, they'll have a war !"
command = {type = trigger which = 171453}
}
action_b = {name = "Let's prevent the war at any cost, whatever it be"
command = {type = domestic which = aristocracy value = 1}
command = {type = stability value = -3}
command = {type = revoltrisk value = 8}
command = {type = treasury value = -300}
}
}
###
### The Civil War (abridg'd)
###
### The begginning of the war
event = {
id = 171453
random = no
country = ARG
name = "The Civil War"
desc = "The king Joan II, not obtaining troops from Aragón and
València, ceded temporally and under mortgage the Roussillon to
England in exchange of military help (treaty of Bayonne). For this
action the catalan Corts declared the king a traitor and looked for
a foreign candidate to the throne. It was the beggining of the
war."
style = 1
action_a = {name = "The traitors are raising armies !! Let's ask
for help to the king of England"
command = {type = revolt which = -1}
command = {type = revolt which = 437}
command = {type = revolt which = 429}
command = {type = revolt which = 427}
command = {type = desertion which = -1 value = 2000}
command = {type = secedeprovince which = ENG value = 426}
command = {type = INF which = 430 value = 10000}
command = {type = CAV which = 430 value = 6000}
command = {type = relation which = ENG value = 100}
command = {type = treasury value = 150}
command = {type = revoltrisk value = 10}
command = {type = stability value = -2}
command = {type = trigger which = 171454}
}
action_b = {name = "The traitors are raising armies, but we can
crush them without foreign help"
command = {type = revolt which = -1}
command = {type = revolt which = -1}
command = {type = revolt which = 429}
command = {type = revolt which = 427}
command = {type = revolt which = 437}
command = {type = desertion which = -1 value = 2000}
command = {type = revoltrisk value = 8}
command = {type = stability value = -2}
command = {type = sleepevent which = 171455}
command = {type = sleepevent which = 171456}
command = {type = sleepevent which = 171457}
}
}
### The cession of Roussillon (informative event for ENG player)
event = {
id = 171454
random = no
country = ENG
name = "The cession of Roussillon"
desc = "At the beginning of the aragonese civil war, the king Joan
II, not obtaining troops from Aragon and Valencia, ceded
temporally and under mortgage the Roussillon and the Cerdanya
to England in exchange of military help (treaty of Bayonne). We
have control now over the Roussillon... but remember, my lord,
that it's a temporary cession."
style = 1
action_a = {name = "Let's hope they forget about Roussillon..."
command = {type = relation which = ARG value = 20}
}
}
### The Treaty of Barcelona (for ARG)
event = {
id = 171455
trigger = {event = 171454
owned = {province = 426 data = ENG}
}
random = no
country = ARG
name = "The Treaty of Barcelona"
desc = "During the Civil War, the king Joan II had ceded the
Roussillon and Cerdanya to the king of England, in exchange of
military help. The treaty established a mortgage of 300.000
ducats for these territories. In 1493, the king Ferran II decided to
recover them and to pay the price."
style = 1
date = {day = 1 month = march year = 1493}
offset = 120
deathdate = {day = 1 month = march year = 1512}
action_a = {name = "Let's recover our lands"
command = {type = treasury value = -300}
command = {type = stability value = 1}
command = {type = trigger which = 171457}
}
action_b = {name = "It's not worth the money"
command = {type = stability value = -2}
}
}
### The treaty of Barcelona (for SPA)
event = {
id = 171456
trigger = {event = 171454
owned = {province = 426 data = ENG}
NOT = {exists = ARG}
}
random = no
country = SPA
name = "The Treaty of Barcelona"
desc = "During the aragonese Civil War, the king of Aragón Joan
II had ceded the Roussillon and Cerdanya to the king of England,
in exchange of military help. The treaty established a mortgage of
300.000 ducats for these territories. In 1493, the king Fernando
II decided to recover them and to pay the price."
style = 1
date = {day = 1 month = march year = 1493}
offset = 120
deathdate = {day = 1 month = march year = 1520}
action_a = {name = "Let's recover our lands"
command = {type = treasury value = -300}
command = {type = stability value = 1}
command = {type = trigger which = 171458}
}
action_b = {name = "It's not worth the money"
command = {type = stability value = -2}
}
}
### The treaty of Barcelona (for ENG, existing ARG) (triggered by 171455-a)
event = {
id = 171457
random = no
country = ENG
name = "The Treaty of Barcelona"
desc = "During the aragonese Civil War, the king Joan II had
ceded the Roussillon and Cerdanya to the king of England, in
exchange of military help. The treaty established a mortgage of
300.000 ducats for these territories. In 1493, the king Ferran II
decided to recover them and to pay the price. We will receive 300
ducats and return the Roussillon to its former owner."
style = 1
action_a = {name = "We accept Aragon re-buy the lands he had given us"
command = {type = treasury value = 300}
command = {type = stability value = 1}
command = {type = relation which = ARG value = 50}
command = {type = secedeprovince which = ARG value = 426}
}
action_b = {name = "We refuse. Roussillon is english now !"
command = {type = stability value = -2}
command = {type = relation which = ARG value = -150}
command = {type = trigger which = 171459}
}
}
### The treaty of Barcelona (for FRA, existing SPA) (triggered by 171456-a)
event = {
id = 171458
random = no
country = ENG
name = "The Treaty of Barcelona"
desc = "During the aragonese Civil War, the king Joan II had
ceded the Roussillon and Cerdanya to the king of England, in
exchange of military help. The treaty established a mortgage of
300.000 ducats for these territories. In 1493, the king Ferran II
decided to recover them and to pay the price. We will receive 300
ducats and return the Roussillon to its former owner."
style = 1
action_a = {name = "We accept Aragon re-buy the lands he had given us"
command = {type = treasury value = 300}
command = {type = stability value = 1}
command = {type = relation which = SPA value = 50}
command = {type = secedeprovince which = SPA value = 426}
}
action_b = {name = "We refuse. Roussillon is english now !"
command = {type = stability value = -2}
command = {type = relation which = SPA value = -150}
command = {type = trigger which = 171460}
}
}
### England refuses (for ARG) (triggered by 171457-b)
event = {
id = 171459
random = no
country = ARG
name = "England has refused !!"
desc = "England has refused our payment for the Roussillon and
will not return our lands."
style = 1
action_a = {name = "Traitors !!"
command = {type = treasury value = 300}
command = {type = casusbelli which = ENG value = 36}
}
}
### England refuses (for SPA) (triggered by 171458-b)
event = {
id = 171460
random = no
country = SPA
name = "England has refused !!"
desc = "England has refused our payment for the Roussillon and
will not return our lands."
style = 1
action_a = {name = "Traitors !!"
command = {type = treasury value = 300}
command = {type = casusbelli which = ENG value = 36}
}
}
### End of alternative civil war, not existing FRA
[/color]NOTE: Remember that you can get the txt file here
), but you're right, I thought you meant an alternative set in case FRA doesn't exist. Well, I'll take a look at the events again to think about the best option. Thanks 
