Hey,
I think it is not really probable that any of the ancistrus-like catfish will be completely safe for paros. The only ones that might have the potential are small species of otocinculus. However, I am not quite sure if the water values would match.
Another option would perhaps be corydoras pygmaeus or the like. I have seen a tank at Dorothees with a nice assembly of acid-soft water loving fish including dwarf corys.
BUT I would not dare to expect either of the fish to spawn or to even have fry survive. Such tanks with a variety of species are certainly an interesting thing. Personally I would rather try keeping small boraras together with paros before adding anything else…