These days, I don't bother with the spot priming of patches anymore. That is sort of old school, though I'm quite sure that many paint store clerks are still recommending that this is necessary. I do my patching and then double coat the walls and everything comes out fine. If anything, I would spot prime with the actual paint instead of using an actual primer. If the primer is a better sealer than your topcoat, then you could get flashing.

White Doves are good. I like the Wooster Pro Dooz and Coronas too. You probably will want to use at least a 1/2" nap for the ceiling painting if your paint is flat.

I don't really think that caulking the trim will help you achieve a better line when you are cutting in your wall paint, but caulking the trim will certainly help you obtain professional results. Caulking is just the right thing to do. There should be no gaps in your trim and there should not be a gap between the walls and your trim. You should be cautioned though that when somebody does not know how to caulk, it can look bad. Most people cut far too big a hole in the tube and then way too much caulk comes out. You really want the smallest hole you can make...even that metal rod that is attached to your caulk gun which is used for opening that hole is too big for interior trim caulking. You want to put the very smallest bead down and then tool it down with your wet finger so that there is no caulk smooshing out from under your fingers. By the way, explaining how to caulk properly is probably the hardest thing to do on the internet...I need to make a video.

To get the best lines, you should paint your trim first, then tape it off with your blue tape, and then paint your walls. You want to make sure that you press down that back edge of the tape so that you don't get any paint bleeding behind there. For that, use a flexible putty knife aimed at the back edge and a small screwdriver works great for getting into the corners.

What he said

especially the smooshing out part

With caulk, as you smooth is as soon as you get a blob on your finger, wipe it off, you may find you can only smooth an inch or two between wipes, but if it starts working around your finger (you are pushing too much in front) you'll have not nice results.

The other thing is to only go one direction with the caulk gun- you don't want to go from the top with the gun up and then "pivot" the gun as you go down so near the bottom you are pushing the caulk with the tip instead of pulling it.

if your tip is pointing down, you should moving UP and if your tip is pointing UP, you should be moving down, same for left and right. I've seen lots of people pivot the gun as they cross the midpoint.

Caulking, along with painting, are two things I will not let my husband do anymore. He can do amazing things with his wood tools, but proper use of a caulking gun or paint brush/roller elude him.

Another thing - paint cleans up much easier while it is still soft. Once it has dried for several days, it will get much harder and harder to remove. I have been able to clean paint of wood surfaces with my fingernails if I do it after the paint has dried but not hardened, like within 4 - 8 hours of painting. The same paint will be darn near impossible to remove after 48 hours.

So I've found the best thing is to paint the trim and wait until it is good and cured for several days. Then put on the tape and paint the walls. I remove the tape as soon as the walls are dry to the touch. I'm careful not to get globs of paint where the tape is as they can dry and you get way more coming off with the tape than you wanted.

Then I clean up any bits of paint that worked it's way behind the tape. Seems no matter how careful you are, there will be a few places this happens.