Fender — make stainless steel .045 – .100 flatwounds like the 9050 set, but sized for a string-thru mustang bass. With Daphne blue or black silks please, and ensure the strings are all nice and smooth like LaBellas or Chromes.
All bass manufacturers: Roll the damn fingerboard edges - It makes any bass (or geetar) feel much better to play; its not difficult to do and doesn't take long, but often (i.e. on all maple necks) should be done before the finish is applied.
I'm guessing that the thumpinator will still have some work to do as the hpf on the cali only acts on the sidechain, not the signal
https://origineffects.com/2021/10/15/cali76-compact-bass-hpf-control-why-it-works/
You'd probably need to be Freddie Krueger to make scratches like that on the pickguard. I suspect it still has the peel-off protective film in place and the actual pickguard underneath is okay.