Can you use a single shot benchrest follower in a Mauser action? Will it work with CRF?

Yes. Maybe.
Only if you get one that has a deep enough recess to allow a round to feed under the extractor; if you get a shallow one, you have to have an extractor that will snap over a rim: a la push feed.

Talked to someone at Score High this evening and they said their follower is deep enough to allow CRF on Mausers. Just ordered one from Midway… on sale at half price and cheaper shipping than Score High.