I had a colleague once, an English teacher of high school mathematics, who was an Alys; so it's got a lively, intelligent, energetic vibe for me.
I'd try to stay medieval for a mn if at all possible. OK, they mostly didn't use mns in the actual Middle Ages, but Alys Tegan would be awful, for instance, and Alys Theresa could be considered. I'd like Alys Margery!