Will do.
It occurred to me after posting this question that I could search around for RFID consultants, and I found one. The good news is there are more certified modules in a different frequency (13.56MHz); And there are plenty of tags and leg bands in that frequency, and it has an acceptable read range, from 10cm to 1m. The only question now is about using a custom antenna, and it appears that isn't a big issue.
He answered the question about certifying tags. It is not required.