A pair of inter-linked push/pulls (vol & tone) for each humbucker will give you all four options on each: series humbucker, parallel humbucker, inner coil, outer coil. It’s a good way to experiment with different combos to work out which sounds work for you.

Then, if needed, you can potentially tweak and simplify the layout to focus on the variations you like/use, ie. neck series/para and bridge series/inner coil etc.