I'll be very surprised if MJ shows up. She's not with Peter and their lives aren't really connected right now...and if they come across a threat that it takes more than two Spider-Men to beat, I think it would work against the book.
I think it's interesting to question...is this a Peter satellite book? Or a Miles satellite book? Or meant to be one for the both of them? Because this is around the time they usually bring back a classic Peter satellite title like the last Spec run or when they did FNSM.