Re: Pagans and Pæga and Paige
First question: I don't think so. The "g" in Pæga is a hard g (ipa /g/) while Paige has a soft g (ipa /dʒ/) indicating a French origin of that name. There is also a gender mismatch.
Second question: I really don't know. A (week) counterargument is: Were the derivation of Pæga from "pagan" obvious, it would be the accepted etymology right now.
--elbowin