For those who don't know, Carol Danvers first appeared in the Main Marvel Universe in Marvel Super-Heroes #13 and eventually gained powers, becoming Ms. Marvel in Ms. Marvel #1. The MC2's Carol Danvers presumably shares the same published history as her Main Marvel Universe counterpart up to a point...more on that shortly.
The only time we see Carol Danvers in the MC2 is Spider-Girl #60 where she appears in her classic black Ms. Marvel costume on the cover amidst other superpowered women of Marvel (including the first female Captain Marvel, Monica Rambeau- see here). However, Ms. Marvel only appears alongside various other previous superheroines in the thoughts of May 'Mayday' Parker as she compares herself to her predecessors. The real world reasons for these cameos was to acknowledge prior female heroes as the Spider-Girl title reaching it's 60th continuous issue, something only one other solo female superheroine title at Marvel had achieved, that being Sensational She-Hulk. The Spider-Girl title would go on to surpass this, reaching issue 100-a feat still unbeaten today.
Jumping into the world of speculation now, let's look at what we can guess at from other established facts. During her career as a superhero, Carol was known first as Ms. Marvel, then Binary during her time in space with the Starjammers team and -most relevantly- as Warbird following her return to the Avengers (Avengers vol. 3 #4). As this Avengers run was running concurrently with the first MC2 titles published in 1998 and 1999, some elements carried over into the flashbacks seen during A-Next #7, such as the costumes and team roster. Despite this, Carol does not appear. What this means is anyone's guess.
It's possible that if Ms. Danvers never rejoined the Avengers, she may not have taken on the moniker of Warbird, leaving it up in the air as to whether she stuck with Binary, went with Warbird or reverted to her Ms. Marvel identity or perhaps adopted the Captain Marvel title of her predecessor as in the Main Marvel Universe. Then again, as noted in my History of the MC2: Heroes Reborn/Heroes Return post, anything beyond Heroes Reborn: The Return #4 is completely up in the air!
Perhaps Carol is alive and well, albeit retired or elsewhere as she remains unseen. Alternately, given the large number of casualties during the Avengers final mission, it's also entirely possible that Danvers perished alongside so many of her teammates. Personally, I'm hoping for the former! Someone should ask Jessica Drew aka Spider-Woman, as the two used to be friends...
Until I recover all my missing memories and piece together my damaged psyche, I remain
frogoat