I had a whole bunch of natives in a 55 before I upgraded. I had an 8" LMB, a 5" SMB a 5" rock bass, six 3-5" longear sunfish, a 4" bluegill, an 8" blue catfish and a 7" channel catfish. It was sand bottomed with a bunch of rocks that I got from the local river from which the fish came. I also had a piece of driftwood from the local river. Filtered with an AC110 and two Marineland HOBs I never had any issues as long as I kept up with my water changes. The tank was too crowded to really have any aggression issues. When I moved them over to the 150 the LMB killed all of the other sunfish except one that seemed to be his buddy.
If you're setting up a new tank just cycle it as you normally would. A few sunfish from the local river would be great for cycling the tank, but you might lose some. I personally wouldn't add rocks and whatnot to a tank of mine again. Just my feelings on it.