Either will work just fine.

Hello I have studied and researched no wax shellac such as (seal coat) you can get by the gallon! It not only adheres to any surface oil or latex but you can also paint over it with either latex or oil so it is a fantastic universal primer to use in your house with your problem! They also say if you have a peeling problem with paint on the exterior of your house due to no vapor barrier on the inside of you house all you have to do is putty all cracks and calk seams on the inside of the house paint over it with no wax shellac such as seal coat and in acts as a 100% vapor barrier no more vapor is allowed to pass thru the shellac it is sort of like a plastic vapor barrier but what is fantastic is you can paint this shellac over the inside wall of your house after properly preping it all loose pait gone and fill voids paint on the shellac it will also be act as a primer for latex or oil based paint great stuff make sure you get the gallon container of shellac that says seal coat cause it has no wax in it or hardly any what so ever or get plain old no wax shellac but seal coat is cheaper and easier to buy ask around and this should eliminate all your problems plus nothing bleeds thru it such as nuts ,or other such things that is what is in the expensive products they sell you they just do not want you to know all you need is the seal coat shellac to solve all your interior problems be sure to put it on in a couple or few thin coats it dries extremely fast denatured alcohol is the thinner or you can get pure grain alcohol from the package store that is 190 prove or better that is more pure and better if you wish and it does not have the poison added to it all denatured alcohol is is 190 or greater prove pure grain alcohol with poison added so they do not need a liqour licence to sell it good luck if you apply you will have great success!! usually it dries so fast it is only 15 to 30 minutes between coats but be sure to wait aleast 24++ hours before you paint over it with what ever paint you choose!!

Different question...is the ceiling sheetrock or plaster? I can't remember the exact reasoning (some one jump in if you know what I'm referring to) but I had a plaster ceiling that would not hold paint. Something to do with the moisture content of the plaster, I think. There is a paint specifically made for that problem. I got mixed reviews from 2 different Ben Moore dealers on whether it would work. It seemed to hold up well. I did this a couple of years ago and have since sold the house and left the paint.

I will never even make rookie status. But, what I see looks like an issue. Do you know Anaglypta wallpaper? It is meant to go over walls with suspect under layers, My daughter used it in her early 1900’s condo bathroom and it was the perfect solution. You paper over and then you paint. Lots of patterns (she did a small bamboo). It’s a miracle for nasty walls. https://www.google.com/search?rls=en&sxsrf=ALeKk030scBsxDpsr8TH0M1vzRi415CWnA:1597529846105&source=univ&tbm=isch&q=anaglypta+wallpaper+images&client=safari&sa=X&ved=2ahUKEwjV1vq3np7rAhWx1FkKHS8VCUAQsAR6BAgKEAE&biw=1280&bih=661