I used a fun file I've had going for a few months to check out Oasis Landing mainly because there is an alien teenager in the household and she not only got caught outside after curfew, she got busted by RoboCop!
Another day, I decided to check out the decendants - two visible aliens. The rest look like her human father and step-mother (pointed ears, blond hair, red eyes, large nose) or her IF (dark skin, purple/red hair, blue eyes) and it was getting dark by the time I found
them so no pictures.
I also checked out decendents with another file I'm playing. I found that while there was a group of six or seven sims on the list, only three looked related to my sim and had her last name. While watching them, because your descendants must have gotten the memo you're in town and follow you everywhere, the eldest of of three that look like my sim reveled he's dating one of the other descendants that look nothing like family or have there name. So I guess these new generic sims in your descendant's houses are like spouses.