You can access the factions screen by hitting either @ or #. or Maybe even ~, I really can’t remember. As it is, it seems that those are just placeholders until factions are worked in-- although by every right most survivors really do deserve to have legendary and heroic reputations with those on the outside, just for surviving and slaughtering everything in sight.
And any way I see it, factions will be worked in after NPCs are fixed, otherwise all freaking hell will break loose with regards to faction affiliations and combat. (that will be fun enough as it is, but for different reasons.)
Google “Dwarf Fortress” and “Loyalty Cascade”. 
As for NPCs right now, v0.3 prerelease still had NPCs active, v0.4 prerelease NPCs were removed (or at least, there are none in my first few evac shelters like usual.) Again, I assume that this was because NPCs being bugged was a contributing factor to the large amount of bugs in v0.3.
It’s kinda like taking a knotted string (aka something buggy) and sticking it in your pocket with some shiny new headphones.
Either way, if you forget about them the next time you’re ready to take them out again and listen to some blazin’ tunes you’ll end up with a tangled mess.
