Regarding the Feige quote, that's a major stretch (no pun intended). Nothing he says there doesn't preclude the changes to the character's origin and powers as I specified.
If such changes do happen, I encourage you to keep an open mind. It could be a vast improvement over the source material. In general, the MCU has improved on a lot of wonky stories and concepts from the Marvel Comics, that wouldn't really have the same appeal to mainstream movie-going audiences.
In this specific case, it makes sense for her to have light-based powers to align with the other Marvels. And they can still keep the iconography (albeit recent iconography) of the giant fists and all the rest using the hard-light constructs that Kamala creates.
And we'll still get our stretchy guy with Mr. Fantastic.
There's no logical reason she needs to have powers aligned with Carol and Monica (also, calling Carol's powers 'light based' is bizarre in the first place, she has one light based power and it's arguably the least significant power she has). The relationship between Carol and Kamala in the comics works great even with completely unrelated powersets. Arguably, it works better with completely unrelated powersets because Kamala isn't in any way a product of or descended from or even that reminiscent of Carol, which makes her choice to associate herself with Carol more meaningful. As opposed to, say, a new archery based hero being inspired by Hawkeye, a new Hulk character being Hulk inspired, a new Spider character being inspired by Spider-man, etc (because who else would they be inspired by?).
Also, the MCU is by no means perfectly faithful in every way but as far as I can recall they have never once changed a character's abilities so radically as what is suggested here, and that's including a WHOLE LOT of characters who are way less significant than Kamala Khan. The closest they've come that I can recall is removing Vulture's vampiric youth-sucking ability (but he still flies around on homemade wings, which was always the most iconic part anyway. EDIT: Actually, I think I misremembered this, the youth-sucking thing apparently wasn't even a standard Vulture ability to begin with, it was just seen once or twice), dumbing down Wanda's powers to 'weird/telekinetic' (but that was clearly just intended to be her starting point for her to slowly grow into the more comic accurate powerset) or switching Redwing into a drone instead of an actual Falcon that Sam has a telepathic connection to (which is, again, a very small part of Sam's abilities). Even Star-Lord's added Ego powers were just a one-off plot necessity that were almost never used and have since been permanently lost, leaving him at basically the same place as comics Star-Lord.
Making Ms. Marvel a Green Lantern-esque character goes way farther than any of that. It would be like removing Captain America's strength/agility and just making him telekinetic instead. I just really don't see Marvel going that far.
The only way I would have ever put much stock in this rumor would've been if it seemed like an attempt to get around having to use the Inhumans or to get around having to show stretchy powers in live action for fear it wouldn't work. But they can easily do whatever they want with the Inhumans including ignoring the previous show or ignoring them entirely and just leaving the origin of her powers mysterious. And - as you already said - they're doing Mr. Fantastic no matter what, so they will have to make stretchy powers work one way or another. So there's no logical reason whatsoever to not also do them for Kamala.
