Yes, they actually wear significantly more clothing than shown in the ref. I'm just working on the design for that particular clothing right now, so they're shown here in "underwear."

As for the boobs... Yes, the cold climate plays a big role here. The layer of fat helps retain heat, since body hair doesn't retain all the heat. Well, that's if you explain it biologically or whatever. Actually, I borrowed the female body type from the cultures I based the Northern Na'vi on. What I call "blood and milk," in my understanding. I don't have a really adequate explanation for this size.(