Mike: Maddie Pryor was a child that showed up in Avengers Annual #10. She was in one panel. The location was the hospital where Jessica Drew had taken Carol Danvers after Rogue wiped her memory and powers. I've always wondered what that was about.
Jay: From my article on Avengers Annual #10 (marvel1980s.blogspot.com/2010/08/1981-avengers-annual-10.html):
“Interestingly, there’s a little girl in the hospital who’s called “Maddy Pryor” and of course any X-Fan worth their salt will recognize that name… turns out those Claremont was a fan of the folk band, Steeleye Span, and of their popular lead singer, Maddy Prior.”
Obviously Claremont liked the name enough that it stuck with him. Also note that this Maddy Pryor had brown hair and was obviously the wrong age (which could be explained by the fact that Madelyne was a clone of Jean Grey created by Mr. Sinister.
Mike: I've also wondered why Mastermind was messing with Mystique in the X-Men: From The Ashes storyline. Throughout that story, he was getting revenge on the X-Men by manipulating them and their colleagues until eventually making them think that Madelyne Pryor was Phoenix reincarnated, but what part did Mystique play in all this? It was Uncanny X-Men #170. She was dreaming she was chased down and hunted like a wolf by Jason Wyngarde and Lady Jean Grey. She wakes to find that Rogue had left her for Prof X. Did Mastermind manipulate Rogue to the good? And to what end?
Jay: Great questions. And I’ve got some answers from the infamous X-Men Danglers FAQ (http://www.oocities.org/area51/rampart/8644/zclaremontdang.html). Apparently, that scene was meant to as a “foreshadowing for a plot planned for Ms. Marvel, which Claremont also wrote at the time. When Ms. Marvel was canceled, the plot was dropped. Mastermind wanted revenge on Mystique because her arms shipping business was siphoning profits from the Hellfire Club.”
Hope that helps!