I skim ready and it sounds like you're using acuto 2k and then a 2k clear?
Anyway, a few comments. If it's all maple you won't get much sink back, but i tend to use epoxy sealers to both seal and grain fill before I do any priming and this is on all timbers. It'll help you level the surface anyway as it's never perfect even after a fussy sand.
I tend to do all my priming with clear coat these days, but I used to use PPG prima primer or other high solids grey primers. I haven't used "primer" on a guitar for a couple years now as I'm getting better results with the sealer and clear. It also helps achieve cleaner mask edges at tricky spots like fingerboard edges etc
3-4 coats of color sounds excessive, I usually spray 2, sometimes three if I have to. But I do spray a tack coat at the start, which is virtually just a mist over the guitar to help with adhesion and avoid runs
Same as above with clear, usually two clear coats is enough if you're using a 1.8 tip. If you're using a 1.4 tip you'll need three thick coats.
Sanding the clear I start at 2000 then 3000 and then buff, however sometimes I'll have done a crap job and have a couple spots I'll start off at 1000, but it's usually 2000.
I don't use microfibre cloths or any of that dirt of stuff. Just a good cut as described above (all wet sanding of course) and then a polish with a waffle pad on an air polisher (variable speed) with a quality 3M polish.