I'm in map 3C and I used your save from map 2 (that you gave me last year) and I don't see Sydran, Grevara, Paxanaria so I don't know about them. Meandor is Undead indeed.
I guess it's voluntary but the Shadow Gate south-west of the surface map (south of the Goblins) is inactive from the surface.
Turn 13-14: Allie has only Lyra and Werber remaining. But the Shadow Demons from Werlac do not attack further as they would probably lose vs the defending stacks of Allie. Seems to be well balanced.
Turn 15: Morrandir sudenly triggers a "The Halflings at Lyra [...]" dialogue with no visible reason.
The dialogues need improving (English and story).
Allie cleared all the Larva Pools at the United cities Shadow Gate, triggering a "Failed: Another player has prevented you from completing your quest". Unsure if it matters for the rest of the map, but would be good to change the behaviour of the Quest or of Allie, because in theory I should count as having completed it.
The Settler stays near the Wizard Tower Ruins on the Shadow layer but does not settle, weird. But I guess we can't do anything about that.
The Outpost of Bleg (Goblin) has no structure in its domain. So when it suggests becoming a Vassal, it makes no sense (2 gold/turn for a cost of 262 gold in my case).
Another general comment: it's quite disturbing that the Shadow Gates are not aligned between layers. That can stay that way and be fine but it makes it harder to know where you have to go and how units move from one place to another (e.g. to follow Allie's or Werlac's moves).
North-western corner of the map, water appears between a Mountain and the void, weird. See image:
By the way, I just saw the Fortress of Rasadac and wonder why Allie controls it with no defender and Serena does not try to take it back. Also, why the "Excavation site" sign, seems weird.
Turn 17: I cleared the 2nd Larva Pool from the northern Shadow Gate.
Turn 18: Werlac's 2 Demon Lord, Harvester and Bombard are still at the smae location, at the border of Lyra's domain, above Trifas' ruins. They haven't moved for 4 turns I guess.
2.3 stacks of Serena appears east of the map, moving towards Werber. All Shadow Elves.
Turn 19: same remark for "Stop the city demons" that Allie completed and which led to Quest failure for me.
North of the Goblins of Hadok, there is a sign "Undefined area", to remove I guess?
South of Lyra, before the bridge, there is an empty sign.
Turn 20: Serena's troops apparently retreated. Not much action in the last 8-10 turns...
I finished exploring the south-west of the map (west of the impassable mountains), it's very empty.
Turn 21: was finally able to Animate a 2nd city: Sparrowdale. Very disappointed that it's an Outpost.

My troops finally passed Lunaris and I started moving on the south-west road to meet the Shadow Demons.
Lost several units fighting the Shadow Demons due to Werlac's Fireball and Magic Fist.
One of my scouting unit followed the road south of Lyra and I suddenly have a dialogue with Kundra, even though I don't see her. Then I get a war declaration and -200 alignment, which causes my morale to decrease (even though it doesn't matter for the Undead units, still annoying). The border of Kundra's city is visible 2 hexes away from where the dialogue triggers.
Esnodil went to attack Lasberg through water.
Turn 22: it seems that me going south-west of Lunaris triggered Werlac's Demons to finally move. The turn after, they butchered Esnodil's troops.
Turn 23: Esnodil's troops got crushed at Lasberg...
Werlac does not move the Larvas he got through Spawn Larva with his Lords' stack, but unsure if there is anything we can do about that.
Serena has not cleared Watchtowers and other structures in her domain, she seems bugged? She takes a lot of time to play (2nd worse, the worse being Mab).
Turn 24: I completed the Harbour Shadow Demon Quest.
Reanimated Fasburg, again an Outpost. :'(
Finally entered UG near Serena's western surface cities (she is still Neutral to me). Triggered a dialogue with Mab. War declaration with Mab, alignment malus... (same issue as reported above)
Turn 25: I reached the Master Shipyard, I was expecting a script to trigger a ferry or at least a transport boat or something but nothing happened. Either remove the "take the ferry" indication on the sign north, or add a script.
(Esnodil has a Succubus)
Overal, so far, I feel the map is a bit too tedious (like map 2 was with a lot of road to travel with not much action): the road to reach Lunaris is long, then to reach the united cities even longer, and there aren't that many sites on the way, and no event. Clearing the Larva Pool is an interesting idea but I don't think it is necessary to have the player do it 3 times, with not much action each time. There was no sense of danger for Lunaris over those 25 turns. There was a small sense of danger for the united cities but then I saw the Demons never attacked them and there was anyway no way I could reach them before at least turn 30...