It would be part of the map itself and the team who won that particular domination battle would have access to it, until it was fought over again.The facility itself would be one of the places you could build tier 2 or 3 stuff, depending on exactly how good a facility it was.
For domination mode? They NPC faction will only be hiring, so there won't be a need to be in any gang or faction. If a group of solo players wanted to get together and play I believe they could.For faction scenarios - I hope player gangs could ally with NPC factions and essentially be counted as members without really joining - but I'm not sure how high up the list that is ... there's plenty of work just getting the NPC factions up and working yet anyway.
So only the ones who participated the fight... interesting. There's no way to lead other players there by tagging?
If you want to make enemies, try to change something.