If you want to reduce issues including agression I'd stick with smaller species which are not known to be overly agressive. The small Panaques (clown plecos, Iquito tigers, tiger plecos, flash plecos) are mainly plant/algae eaters and need wood in their diet. The various varieties of common bristlenose (i.e. regular, albino, calico, and I suspect GBA's) would look great together. They all come as long finned forms and would do well with the small Panaques. You can also keep Peckoltias (big band tigers, Peckoltia brevis) together with some Hypancistrus (chocolate zebras, king tigers). Males of all species can get a little stroppy with other males, particularly ones of the same species, or similar patterned ones. Make sure you have plenty of cover (wood, rocks, ornaments, etc.) and I like to separate piles of wood or rocks apart to give fish that are picked on a break. You shouldn't have many issues at all until your plecos are mature.
Hypancistrus (chocolate zebras, king tigers, queen arabs, zebra plecos) will readily interbreed and produce fertile hybrids.