And it looks like it will go back to what Heroes II, III, and V were, not the dog that was VI.
As for factions...Haven, Necropolis, Academy, and Stronghold are in. But here is the catch, the last two factions will be voted on by fans.
The first is Sylvain (Elves) vs Fortress (Dwarf). I think the elven faction wins here and its winning right now. The next battle will be Inferno vs Dungeon. This should be an easy Dungeon (dark elves in this continuity) victory. So basically the six factions are likely to be the classic Heroes II six.