I'd like to know more about it.

As I understand you don't need to change race or anything, you just go from the "Strong" faction to the "Weak" one determined by some ingame mechanic. So I assume that means you can be a Nuian Alliance Firran or a Haranyan Alliance Dwarf or whatever. But I've heard that it wont be permenant, soooo...

Is it permanent? (I've heard it may only be a temporary switch)
Is there a cost associated with it?
Will we for sure have it in ArcheAge: Unchained launch?

I'm having trouble consolidating a group of friends into one faction since they have different preferences for maps, housing, racial skills, aesthetics etc.
All of which could be easily bypassed just by knowing that we can all pretty much do whatever we want and it would be possible for one side of the group to migrate to the faction of the other side of the group depending on which ends up being "strong" or "weak".