Interesting vid. As for the gangs that will be included, if they follow the Mordheim template, they'll start with 4 and later add 2 as DLC (maybe more if the game is more popular?)
I would assume they'll start with Goliath and Escher (same 2 as in the upcoming tabletop re-release) plus Orlock (standard biker gang style) and probably Delaque (trenchcoat assassins). For the DLC, I assume Redemption and Scavvies.
Hopefully the game will be popular enough to include even more, but at the least some characters (Spyrers? Enforcers?) could be included in special missions and others (Ratskins? Pit Slaves?) could be DLC characters like the Wolf Priest and Doomweaver in Mordheim.