They’re still doing a Kamala Khan show, right?

That's the rumor. The one actress that's supposedly the frontrunner kind of shot down those suggestions though. 

Also, he's a fan of Stark.  She's a fan of Captain Marvel.

There's no more Tony.  So him being a "fanboy" is not a thing anymore.

In that case 99% of the major superheroes are redundant because how many share almost identical  catalyst to being heroes or share identical personality traits?

Being a fanboy and fangirl respectively doesn't alter their value in the movie long term, look at Stark and Strange giants in their field with huge ego's and arsehole personalities, tragedy befalls them and they must struggle to repair the damage caused to them, both turn good but serve very different functions in the team up movies and will likely end up playing vastly different roles in the overall MCU by the time Strange leaves the franchise like Stark has.

Like Peter was approached by Tony and became an even bigger fanboy, trying to bother and impress Tony, Kamala could approach Carol and be taken under her wing as her actual sidekick or protégé, with Carol directly or indirectly taking a more active role in Kamala's development as a hero. 

Also doesn't the she's redundant argument also apply to every additional variation of the same characters, like isn't EVERY animated and live action version of Spidey then a redundant regurgitation of the character? What makes characters the same doesn't invalidate them, it's what makes them different that validates their existence, and Kamala is a very different character to Peter that they could explore easily.

Not really, he had a couple of major moments but Spidey was mostly going on his own initiative, Kamala could actually be trained by Carol and given lessons or missions from her, either in person or via a proxy, even Happy who was Tony's proxy to Peter was mostly hands off, telling Peter to just cool his jets and stuff, not sending Peter special missions of training exercises. 

Actually it's more like he's trying to impress him, for a reason, he wants to be an Avenger so he thinks impressing Tony will get him there, in FFH he's trying to make Tony proud, because in FFH he's trying to live up to Tony, keep his legacy going in a way, he doesn't want to let Tony down, for no other reason than how he feels about Tony and what Tony did for him and everyone else, in HC he's trying to get something out of Tony, recognition and status, you know you can impress someone for going against their wishes, not so easy to make them proud by ignoring them, though in HC he does do both, by impressing Tony he makes Tony proud of him also.

Kamala could try doing both but for different reason, so Carol doesn't regret making Kamala her protégé as well as upholding the values the "Marvel" name represents, as such unlike Spidey who doesn't need to worry about tainting Tony's legacy as much considering he is Spider Man not Iron Boy, Miss Marvel would have that hanging over her, her actions could reflect on Carol.

Like I said differences is what matters not the similarities, because most superheroes have similar backstory elements anyway so why the fuck is this an issue here but not there?

That's a bit disingenuous.

Whether you think the character can carve out her own niche in the MCU or not, it's more than clear what makes her unique.

Ms. Marvel is a Muslim girl that was created specifically to cater to female readers.

And, the bottom line is that she won't overlap with Peter if Sony and Disney can't work out a post trilogy deal. In that case, this is a non-issue.

Kamala Khan's grandparents may have been cast.

movieweb.com/fawad-khan-mehwish-hayat-kamala-khan-grandparents-ms-marvel/