Cowl vent paint question - 66 Stang

Monday I'm going to go down to the local paint store for some supplies, but I'd like to have it planned out before I get there.

From what I have researched, is this the correct process to take before welding in the cowl patches? (for the underside of the patch panels at first)

1. Use wax & degreaser to clean the metal, I noticed it is oily and I assume that is for rust prevention
2. Sand piece for primer adherence - what grit is best on bare metal?
--wipe off debris and ensure patch is dry--
3. Use Etching primer
4. Topcoat etching primer with paint - no need to sand the etching primer, correct?

Use the degreaser again after sanding and then when it dries you can primer ontop of that?

After using the degreaser, is it necessary to wipe down the patch with water and a rag to remove any chemicals left behind, or is it a striaght shot on application of primer after using degreaser?

Does epoxy have come in an aerosol spray? I don't have the option of using a spray gun on this project...

If I go the epoxy route, I degrease, wipe down with the cloth, spray expoxy and then topcoat?

Thanks for the replies!