no personal exp with the other fish but friends of mine do. they have 30cm gars with 5 cm plecs and 30cm tsn with 5 cm plecs so i guess it should go well. but on the other hand, ive read stories about tsn eating a lot...
Large bottom dwelling carnivores are a no go with smaller plecos, for a pleco that is already 8" SL? they whould be fine. The top dwellers will be no problem as long as they are well fed, and there are things for the pleco to hide in.