OTOH, it could be interesting to find out that there was only ever one Cassie, and that MC2 Cassie *was* 'our' Cassie, displaced interdimensionally, having adventures in this other universe, which she's either forgotten (did she choose to have these memories erased, or was it done to her?), or had to keep quiet about, for... reasons.
(It might even be tied somehow to her occasional uses of the Stinger identity and gear in 616, instead of the Stature identity, that Stinger phase being right after she 'returned' from her time in the MC2-verse, where she'd been operating as Stinger for awhile. Being time-shenanigans, she returned seconds after she left, months older, and with new gear, and her friends never even knew! It could also tie into her fairly rapid off-panel maturation as a hero, where she's now kind of the voice of common sense and experience *to her dad,* because she's got the benefit of a bunch of super-heroing that some others don't know about.)
But not the evil Ultimates version. Yuk!