Which companions have romance options

Starting with late beta, companions share your alignment. I remember I switched from neutral to full light, and suddenly a bunch of items my companions were using couldn't be used anymore since they said 'forbidden for light I and above', even though it was my companions who were using them

You'll need to do your class quests at a minimum if you want to unlock the full compliment of companions, which is important if you want to keep your crew skills up to date. You'll need to do them through at least level 15 or so to get your ship to be able to get to planets other than the starter areas as well.

Questing is also one of the few reliable ways to bring in credits, and at high levels, skill training becomes extremely pricey.

You can play with a minimum of questing, but the hoops you'll end up jumping through may make it not worth doing.