I can answer about primer. Primer doesn't have the same properties as paint film. It actually has a time limit, need to apply top coat sooner than later because it will break down and flake.

I didn't connect the dots until a few years in this gig. Builders sometimes mix primer into the final ceiling skim coat and not finish it with top coat. After about a year, you start noticing extremely fine white dust. Everywhere. The ceiling is literally flaking.

When we paint the ceiling, magically you don't have to dust twice a week.

Paint and primer in one is made to go over already painted surfaces that are latex and don’t have stains. If you’ve done repairs or there are stains you need to spot prime with the appropriate primer. You also want to caulk after primer for best adhesion. I’ve always been ok with good old Alex but Sherwin Williams and Ben Moore sell others.

Caulk - If you want affordable(ish) Sashco Big Stretch. If you want to spend more any of the 55 year isometrics will work great.

Interesting about the primer - that could explain some flaking off of previous paint jobs. I had thought the opposite, that it gets too hard... or something. So then how to replicate the bright white chalkiness with paint - not something I would ordinarily do but it is looking fantastic in combination with a LOT of dark vintage wood and even Chantilly Lace is looking dull in comparison. LORI I'm a fan of your website but somehow missed that Chantilly Lace is green (!) Have heard of people using white base with extra white colorant added, but who knows where that would go! Plan B is just to find a white that is red instead of green (to better harmonize with wood) and call it a day!

Ive only had disasters with Alex - supposed to be paintable, and it is, but then the paint above it stays eternally sticky and attacts dust/dirt which doesnt come off. YMMV as they say! Other painters caulks just crack open the very first change of season, will try some of the more expensive options.....