I have a fanned fret custom bass I designed myself. Link:
https://www.talkbass.com/threads/a-different-custom-p-style-bass.755914/
OK. If you want to use stock-style pickups, remember that when you rotate the pickup to match the fanning, you effectively narrow the string spacing. So...
1) You may want to use a bridge with a slightly narrower string spacing than the Fender-standard 3/4 inch/19mm string-to-string. I suggest looking at the Hipshot plate bridge options that come in a selection of string spacings.
2) If you want a stock-style mudbucker, it has one row of pole screws so you can rotate the pickup to match the fan, with the above caveat. As with Gibson/Epiphone, I would put it pretty close to the 24th fret position to assure the strings do actually go over each pole piece as the strings narrow from bridge to nut.
2) I would suggest a J-bass 1 1/2 inch nut so that the strings do actually narrow. This is a flaw in all Fender basses: I'm sure the mule neck that Leo used to design the pickups had the 1 3/4 inch nut, which made the strings on production basses fall outside the center between the pairs of pole pieces, especially on the E and G strings. So on the classic bolt-stock bridges you had to move the E and G strings over one notch in the saddle to center on the pickups, especially when Leo set forth the options of a 1 5/8 nut for P-basses and 1 1/2 nut for J-basses. But with Gibson-spaced mudbuckers, such as the ones made by Artec, they will have the narrower traditional spacing.
3) Leo used this same Fender-standard spacing for a MM pickup. So when you rotate this pickup to match the fanning, you can run the strings through the middle of each set of poles as rotated with the pickup, so long as you have it in the MM or J-bridge position.
4) If none of this appeals to you, several manufacturers make pickups in these shapes that have bars instead of individual poles. Of course, this obviates the pole/string spacing issues.