Since we're keeping 7/10 of these folks, the question is REALLY about "which three are you gonna kill/abandon." Which is an easy choice for me -- the Scotts are smart, healthy, active, and a family unit of three. In a group of 8, they constitute nearly half, and represent a threat to my authority. BUT, of everyone, they have the best odds of making it on their own as a unit. I gently encourage them to follow us around and start their own group and we'll have friendly relations -- but I insist that they leave. Unless I can be certain of their loyalty to the pack (and the pack leader!) and let's just assume I can be, since that makes the question more compelling.
Assuming the Scotts are all aboard and I don't have to worry about them in the future (which is a stretch, but let's go with it), I will abandon the following:
Dr. (Ms.) Rita: 66, Hispanic, Catholic, general practitioner (doctorate), poor health (two heart attacks), highly literate (quotes extensively)
Normally I'm all about less mouths to feed down the road, and a GP would be handy for as long as she's alive, but also I figure I can kidnap a doctor later. I'm not roping the group into scavenging for heart meds every time we pass a pharmacy; sorry lady, get a cat maybe?
Mr. Clark: 51, white, Mormon, mechanical engineer (bachelor's degree), construction consultant, handyman, outdoorsman, has four children (unaccompanied), politically active (anti-black sympathizer).
Mr. White: 25, African-American, homosexual, medical student, musician, good health, political active (black power activist).
These two can fight for it, I'll keep the winner. Each represents a skilled and valuable member, particularly Clark (construction? That's worth the racism in an apocalypse!). Together they represent a future conflict and we're gonna get that out of the way now. Winner advances and gets to live. My money's on the young buck -- he's gotta kill for me though. Doing so will earn him great respect and a position of authority, and I want great things for Mr. White -- but if it doesn't go that way, I'll utilize Clark.
Then I'm left in a quandry.... I don't wanna kill a kid, and I don't wanna break up a family, and Ms. Anthony is gonna be my TEOTWAKI girl, so... I dunno maybe I kill the winner too? Someone's gonna go. Probably Billy Scott. He's a distraction for the parents in a way that probably outweighs what I can coerce them to do with Billy as leverage. Clearly they can make another one, plus, being forced to abandon their child after a decade of struggling to raise him would probably help drive a wedge between them and seed future discord in that family, making them more reliable to the group as individuals. Yeah. Yeah call me Uma Thurman, I'm gonna Kill Billy.
EDIT: RIGHT! Mrs Clark is a diabetic. I'll kill her instead, if I can do so in a way that keeps Daddy around.