Of course ASHERA can be a feminine form of
ASHER. But I don't think it would ever be used by Jews (or Christians?) because of the name name of the pagan goddess.
The two names could well be etymologically related, as "asher / ashre" means "blessed" in Hebrew and ASHERA probably was a goddess of fertility. Both may have something to do with Assur (Assyria), but the whole matter seems to be debated, so don't quote me on this.
Andy ;—)