I think the parole officer is on the Healer tribe, which still makes little sense. The one that confuses me most is the financial advisor being on the Heroes tribe. She was the half of the mom squad that did not go home.
I did hear in a pre-season interview that the cast was chosen and then the theme, not the other way around. They already had the players they wanted, then noticed that they (for the most part) fit into these various groups.
I don't mind this theme, because it is interesting to see if the players take the branding they've been given and run with it, or try to break away from it. For example, being put on the Hero tribe will give others the impression that you're probably an honest, loyal type. After the merge, I could see one or more of them trying to play that up, to gain trust and then stab people in the back. Similarly, being on the Healer tribe you might play up your empathy and compassion, which makes it all the easier to draw people in to get them to do what you want them to. I think the Hustlers are at the disadvantage with this theme after the merge, because they don't have as many positive traits associated with them that you would want in an alliance member.
If anyone is interested in listening to Survivor podcasts and doesn't already know about, I highly recommend
Rob Has a Podcast (RHAP). It's hosted by Rob Cesternino, a former two-time Survivor player. They did several pre-season interviews with the cast that I am still working my way through. There's also a recap and interview with the person voted out every week. He covers Big Brother too, when that's on.