Help putting together and selling a supplement for a game on DriveThruRPG?

So, I'm making a supplement of the old TSR Marvel Superheroes role-playing game from the 80's. I'm reworking quite a bit of it to fit Julian May's Saga of Pliocene Exile and Intervention and the Galactic Milieu trilogy. Surprisingly, the system fits it really well with the MSH Advanced Set. And I want to make it compatible with FASERIP, if possible.

First, I know almost nothing about FASERIP and would love any help with setting it up for that.

Second, I have no idea how or where to get permission to do this "officially". Would anyone know who I can contact?

Third, I need to find some Graphic Design help. I've made a couple of pages in MS Word, and they look good, but I just don't have the time.

Because Fourth, I'm still creating the supplement and doing Game Design. And I could use some help with that as well.

And I also need play-testers. Does anyone know how I can get play-testers?

If you want to take a look, it's at r/Metapsychics.

I got put on Disability back in 2019, and I've been working on this off and on since then. And now I'm going back to College to get retrained, so I really don't have the time.

But I think a lot of people would like to play it.

Would anyone be interested in any of these?