Gia’h having access to all the powers doesn’t mean she knows how to use them all effectively. Some may be too much of a strain on a body that didn’t obtain them naturally, there’s plenty of ways to write around that.

The US declaring war on all aliens is actually how the first SWORD miniseries at Marvel began so I assume that will be an adapted plot somewhere, plus it kind of feels fitting in a world where aliens have attacked Earth several times over and killed half the universe.

The only upside I see to President Rittson’s misoxenistic (edit: how do you construct the word for ‘fear of extra-terrestrials’? this one seems to mean fear of strangers) response is that I feel like it really primes the stage for a natural progression into a fear of mutants that’ve suddenly started springing up. If you were a normal human and someone close to you seemingly “lost control” and “let their powers slip”, and you’d seen the footage of Skrulls (and maybe some out-of-focus footage of a Super-Skrull), wouldn’t you feel completely justified in indulging your xenophobia?

In reality, the Skrull letting their powers slip would just be an instance of a young teen manifesting powers they don’t know how to control. Powers manifest in high-stress situations near the onset of puberty, iirc.

Not every superhero will be frowned upon. Some will be considered “the good ones”.