P.S. There's a strange issue with the HD mod during Fortress Battle: Archdevils don't fully heal under the effect of Elixir, and the Sphere of Earth doesn't work for resurrection (though it might be intended).

Elixir only heals for 50 HP. Spheres only affect attack magic. This has always been the case in SoD, and it's a well-known fact, so there's no need to blame the HD mod.

By the way, yes. The opponent had artillery and control over the Towers. Before firing, he revives the Archdevils, then fires, but the Archangels don't move afterward, while my upgraded Wyverns move first. It's strange.

If a stack has already moved in a round before its units die, they are resurrected as "already moved," even in subsequent rounds. However, if the stack was only waiting to move at the moment of death, the wait time doesn't carry over to the next rounds.
There's also this feature: if players have the same maximum creature speed, after the Catapult's turn, the attacking player always gets the turn advantage (contrary to the usual rule, where the player who didn't move in the previous stack gets the turn).