SAPS with African Butterfly Fish and Purple Spotted Gudgeons, even Golden Wonders, are poor tankmate choices. I'd happily put the last three together (I have ABF and GWK), but absolutely no way with any puffers!
SAPs want a strong current, something that really is the worst you can do for the others.
SAPs need speedy tankmates, look at species with forked tails, for instance Bleeding Tetras or Filament Barbs (in a longer tank). Those tankmates are usually extremely sedatory.
SAPs should not be kept with tankmates who have elaborate fins, those long spindly pelvic ray fins of the ABFs will be very tempting and nipping will highly stress them.
I would also up the SAP numbers to at least five, you could do even more in a 50g.
An oddball riverine bottom dweller? A Steatocranus (African Blockhead Cichlid) species, I have ~50 S. casuarius (because of youngsters) and a brand new pair of young S. tinanti. They will love and need the current, plus the densely furnished areas of the tank needed for the SAPs will make perfect areas of cover for these cichlids to hop between.