Hi Mitty

I really don't know how i missed your post from earlier. good progress though. I agree with waz but heres my addition

Shielding - Shielding paint is not my preferred option, because if you don't like it or its shorting something, its difficult to remove. Noting wrong with using shielding tape for humbucker routs and your control cavity.

Pre-drilling of holes - I normally wouldn't pre-drill the holes before spraying, but if its done as waz said watch out for water seepage when wet sanding.

Bridge Grounding - I agree with Waz.

Tight neck pocket - a bit of sanding would sort that out, when the time is right

Top Clear - I am by far not an authority on this. I've used an enamel colour coat with an acrylic finish (both rattle cans and work very well) but they were the same brand and recommended to go together. If you have used a generic brand from the big green shed you should be able to find a top coat in the same brand. Otherwise consider White Knight Acrylic or a polyurethane such as cabots cabothane, which are readily available, don't cost much and you can test on a piece of scrap wood.

Good luck mate