I mean, no comment on whether or not there's already a box of nice smooth rocks on a shelf in the garage...
A thing that I'm also trying to keep in mind regarding fish types is that it's an open top so I don't want anything that jumps too much either. I've been going back and looking through all of Rachel's species spotlights on hillstream types. Rosy Loaches? A huge group of CPD's if I don't want to go full hilstream? There's lots of gobys out there but it sounds like finding a type that doesn't need salt water for breeding is another consideration. It's all going to be slow going anyway, the fish budget isn't huge.
Ah, the deeper story!
All those things sound good. I have been watching (almost) all the spotlights from Rachel and have her nano fish book which she signed for me at a conference where I had the chance to talk with her for a few minutes. The "nano" fish are also my favorite and she is one I appreciate for her spreading solid information to the hobby, concerned about genetics, collection, importing, keeping and promoting the hobby - so helpful and kind.
Gobies are a fish I really like but do not really know much about. Stiphodon annieae aka Annies Goby are a fish I was watching for a good deal on a few. Very hard to find and about $18-25 each. So having spare money if I find them is also a "thing".
CPD are a gorgeous fish, and some people can breed them!