Round table

I took down the demons, not on the first try, but I got them, losses were 3 air and 1 sword, I think. The archers had a morale proc somewhere. I took the angel external dwelling with archers and centaurs, plus all the pikemen and single-unit pikemen. Centaurs down, archers up, main pikemen as close as possible to the archers to cover them with the single-unit pikemen on the first turn. In the first round, a single-unit pikeman absorbs the retaliation from an angel, and the centaurs hit (with the archers shooting, that's exactly 1 angel down), then the angels ignore the centaurs and kill the pikemen. Luckily, 2 angels wiped out the main pikeman stack, leaving a single-unit one to protect the archers; the archers got a morale proc once (what with +3 morale), total losses were all pikemen except for 2 single-unit ones.
As for the Manticores, also not on the first try; I was adjusting the deployment. I managed to split the Minotaurs decently (deployment: Harpies, Dendroids, Dwarves, Centaur Captains, Griffins, Pikemen, Centaur) - but several stacks hit the screening force of Dwarves and Dendroids, so in the end, only a few Centaurs died and all the rest except the archers. An important move on the first turn, imho - Griffins in front of the Harpies to lure 2 stacks into a full volley and then finish them off. The Unicorn external dwelling was taken with only the loss of single-unit Centaurs.

The main thing is - in all 3 battles (except the angel fight), the terrain very luckily preserved the screen and allowed me to split and maneuver them back and forth more or less (one Minotaur of mine actually went around the entire battlefield). Also, I should note that the mobs didn't have overly troublesome morale, but if they had, goodbye; the angels could have easily gotten a morale proc and goodbye archers, same for the Minotaurs.

In a real game, you'd of course have to think hard about it. But, by the way, the strategy for the Manticores is strange - the second road isn't scouted by week 1, day 14, it takes half a day to go there, and there's the Dwarf external dwelling (they would have definitely helped in the fight with the Manticores to save the Dendroids), although it was probably a lack of gold that played a role. I played through to week 1, day 17, went down that road to the Citadel, Elves, Centaur Captains, and Rogues cleared everything.