I would skim that drywall, THEN prime or suffer the cost in paint that will never ever prevent the bleed .

Skim/mud the whole wall. First.

Sounds a bit boring too........you can always do a great peel and stick mural....

Hadn't thought of that method. Probably cheaper than a coat of Zinsser 1-2-3, then another 2 coats of Zinsser BIN primer, plus what ever color we choose.

Should we stil do a light sanding before the skim coat?

Just get a pro to skim AND paint. In the end? Probably a better result, smoother, and better coverage.

You don't need to sand it prior to skim........unless it looks thick and gunky.?

It’s just paint. Sand it lightly to remove any drips/ runs. Two coats of primer, two coats of paint.

Painting is more in my skill level. The largest area I've skimmed is about a 3'x4' repair job.

This wall is an upper floor room in a gym, so the ceiling is curved, about 12' up and about 20' wide. Talking to Building and Grounds committee about getting a platform up the stairs.

2 of our teens want to get this done before schoool starts, and have painting experience. No one else has volunteered, so far.

I agree, two coats of a bonding sealing primer, and a couple coats of paint, and it should look just fine.