I can rec previously recc-ed stories from calufrax, right? (Likely if I do that for a square I will aim for 1 older rec along with least 2 new ones as well.)

Oh, yes! This is a new comm, and I wouldn't expect for everyone to check back to Calufrax. And repeated recs are okay here anyway, as long as people try to avoid doing it too often/too soon.