- Which faction is stronger? (Necropolis, Tower, or Conflux)

Well, yes... but who will allow the enemy to REACH the master gremlins? :D I, for example, don't allow this in 95% of cases... and if someone does reach them, it's in such a small number that it's not even worth talking about (of course, I'm talking about the beginning of the game - when there are no mages, let alone titans).
Undead have it tough - level 1-3 units are practically useless here... at the beginning of the game. Skeletons are strong in large numbers... but there aren't many of them here. Zombies are just meat... slow and stupid... a nightmare, basically... I don't even consider them as units. I don't build ghosts in 90% of cases! So, there you have it - what a fun start! If there are no vampires, everything, development is terribly slow.