Repaired nail pops and primed with a brush. The areas are shiny spots showing through the ceiling paint. What is the best way to fix this problem?

I’ve scrapped, repaired, de-rusted an old tin ceiling. I primed it with a oil-based rust inhibiting primer. I was planning on using oil-based paint as the top coats. Having a hard time finding any. Can I top coat with a latex paint? Thank you, Lisa

My well meaning but short-cut minded friend applied new skip trowel drywall over sheetrock where there had previously been paper in a bathroom. He then applied a coat of semi-gloss latex enamel. I was upset when I heard that he had skipped the primer. Aside from the obvious repercussions like

I finished painting a bedroom approx 30 days ago. There was a spot on the wall and when I wiped it off a hole appeared and the paint could be peeled off in one large sheet. The wall had been primed with Glidden primer (water based over latex) and lightly

I ordered and received a new fiberglass entry door but unfortunately the stain was not done to my satisfaction. How can I strip and restain the door to a lighter shade? Should I also consider having it done professionally? Any idea how costly that would be? Thanks

On new construction; when you say so much a sq-ft is that for each coat? Or to the finish coat (3 coats)? What about trim?