Man without all the DLCs I wouldn't be able to give you completely correct tips since I honestly don't know which dlcs give which benefits. I can tell you that you need right of man and art of war. But as far as the plan goes. Its usually best to ally Castille use them to conquer Morocco, try and screw them out of getting a PU or at least delay it, I don't know if you get the unique missions or not I believe you do since you have Golden Century. Honestly if you can conquer and form Spain. You can complete the 35 missions Portugal gets then convert to Spain and finish their 35 missions as well you'd be a colonial powerhouse.
As far as colonizing goes I like to go for the trade companies rather than the new World. Trade companies and especially the Ivory coast and Cape of Good hope Nodes give so much more money than Caribbean. Personally I haven't played Portugal, but have played Castille more than enough times to know about the Iberian Peninsula.
I wouldn't keep the English alliance since they have their own problems in the beginning of the game you'd be better off allying Castille and a rival of theirs or France. You can also use the Pope to your advantage if you get Curia you can use crusades on the Small African nations in the Congo or excommunicate.
I think this goes without saying but getting exploration and expansion ideas ASAP
Thanks in Advance
