heres another option.
Gwen and her family are 5th dimensional beings.
Bat-mite+Q from startrek.
all powerful gods. bored with reality, so make fictional ones to play roles in. They are playing at being a mundane human family.
Gwen has lost herself in her role a bit, and her powers are leaking out. Shes making portals to the Marvel universe, subconsciously. While her brother keeps pulling her back into the proper storyline.