Comments and my experiences.
Despite a lot of lakes not a lot of GOOD fish diverse private hatcheries in SE MI.
HBG - will bite, on a regular basis, the hell out of your swimmers - girls/females will hate you for putting them in the pond. Men-boys tolerate HBG bites better than females. Large HBG can cause mouth scrapes that seep/ooze blood. I can supply phone numbers for testimony.
RES - will only bite and bump the swimmers in the beach area during RES spawning season in MI which is June.
SMB is a good and better alternative to LMB for your situation. I did not suggest them for you because you will have a lot more difficulty finding them. Stock them if you can find them. SMB will not prey as hard on minnows as LMB. YOU could combine SMB and yellow perch. Neither will bother swimmers.
You could stock walleyes and perch neither will bother swimmers. Walleyes may also be real hard for you to locate.
You will need good experienced advice for these two-three fish combinations in a low input swimming pond. Also a combination fishery will take more of your time to manage it properly so the fishery produces decent sized fish and or an occassional fish meal. Clear swimming pool water produces few fish per acre.
Adding minnows is an option. Problem with that is the more you add the bigger the bass get and then the more food they need to maintain their present health and body condition. So you are caught up in a circle. Rarely will minnows be able to sustain themselves in a pond situation that you are hoping for - mainly swimming. Minnows need weedy and structure filled settings to maintain their numbers. Golden shiners are an option for you but very difficult to find. Swimmers do not like weedy, structure filled, cloudy, green, tinted water ponds. Swimmers want clean, clear blue water; fish don't. At least numerous big fish don't.
Ever consider adding just some minnows and then plant 50-100 trout from Spring Valley each September? Trout will survive in your location until early June maybe late June in some years. Minnows will repopulate during the absence of trout. In fall minnows will be abudant to feed each annual stocking of trout. If you don't feel like stocking trout every year in most cases that will also be okay.
Bullfrogs will not become establised very well (maybe 1-3 per acre) unless there are some emergent plants along the shoreline on opposite end of swimming area to protect and shelter the adults. Trout option vs bass option will allow for a lot more frogs.
