Need help! Got a used traeger and there’s rust.

I got a great deal on a used Gen 1 Timberline 850! 600! But that comes with a cost, needs a little TLC.

1) Found the rust pattern on the back means there was likely a fire. Started useding Rust-Oleum rust remover and have a carbon steel wire wheel I'll use to remove what's left after a few applications. Then coat with a high heat grill pain.

The inside is a bit trickier
2) The two back vents are rusted, particularly the left side. I don't know how to approach this. I keep seeing everywhere NOT to use Rust-Oleum INSIDE the grill. I haven't, but I don't know how to get rid of that much rust in such a difficult place.

3) Rust all over the firepot and grease trap.

3) The last pic is the reflector plate on the front inside next to the grease trap. They screws were rusted and when I tried to remove them they got stripped. No idea how to approach that without too much damage. Can I drill them out? Do the screws absolutely need to be replaced?

First time I've ever been able to own a grill due to living in apartments and xyz and these are the last speed bumps till I can fire it up.