When I was keeping sunfish, the pumpkinseeds were around 5 times as aggressive ('aggressive' defined as persistence in tankmate bulliying) as the bluegills. It might be down to the individual fish, but I think it is worth noting.
Outside I have a 55g with three very large dojo loaches. I'm interested in sunfish, either bluegill or pumpkinseed. How would these do with the loaches?