The problem with no pickup rings and direct mounting is the problem that started this in the first place, the oversized and not well shaped pickup routs:
https://uploads.tapatalk-cdn.com/202...0825fb5973.jpg
Any direct mounted pickups will look rather silly sitting in there.
Unless there's a cunning plan in the offing, Freakystyley seems to have missed the opportunity to fill the routs to make them a normal size, and has also left the two strange holes at the top and bottom of each rout unfilled as well. Any filling would now require a respray.
My only suggestion to mount the pickups without more filling and painting is to get some clear acrylic to make a mounting plate for the centre section, and spray the reverse with the blue and cream to match the blue and the stripes. You'll need to paint the reverse to hide the extra large routs. But you'll need to be comfortable routing out (or cutting out) standard humbucker-sized holes in acrylic/perspex to do so (and not scratch the surface whilst doing so).