I was looking through a few things in maybe figuring out what their traits in Sims 4 would be, and I did find a few things.
Chris Roomies has a very high interest in Outdoors, Parties, and Technology. So her possible traits in Sims 4 could be Loves Outdoors, Geek, and Insider, if you have Get Together. If you don't have Get Together, her personality also leans heavily towards the lazy side of her personality, so if not Insider, then Lazy.
Melissa Roomies has a high interest in Politics, Music, and Hollywood. So her possible traits in Sims 4 could be Self-Assured, Music Lover, and Outgoing.
Now as far as their last names, back in Sims 3 there were two households that had roommates, and a couple of the sims would make me think of those two girls. Monika Morris and Blair Wainwright. If you wanted to go with their last names, then my suggestion would be Chris Wainwright and Melissa Morris.
