I don't see how this could be canon. But Moongirl is a poor seller and I doubt Marvel cares. IMO, this is a stupid title not really intended for mainstream Marvel readers.
Here is a quote that appears in the issue:
Moongirl: "Hold it right there Surfer. I'm smarter than Mister Fantastic ever was. That's a fact."
Apparently no one believes Marvel on this point, because the writer of Moongirl makes sure to tell the reader over and over that Moongirl is the smartest person in the Marvel Universe. She's the smartest. No really....she's the smartest. Seriously dude....she's the smartest.
Johnny just flies around doing virtually nothing, despite the fact that Galactus has appeared to warn of pending doom. Ben is largely in full teddy-bear mode with a kid riding around on his shoulder while he tries to do something.
Moongirl makes Valeria look like well-behaved, respectful kid. In fact, I don't think I have ever seen a more annoying character than Moongirl. I downright miss Valeria now and want her to come back just to "sweep the leg" of Moongirl. Dumbest title ever. Putting FF veterans in this title disrespects the FF legacy.
Moon Girl has no redeeming qualities whatsoever to make her endearing or even bearable to this reader. The entire books a pile of crap that needs to be flushed.