Beware of buying your redear from a truck at the local co-op. You have a very good chance of getting unwanted bgill or hybrid bgill contamination with the purchased fish. If you want a pond with only RES, be sure to buy them from a very reputable hatchery and explain to the owner why you want him to carefully sort your fish so you only get redears. Contamination of other sunfishes will eventually ruin your predominate RES fishery.
This is a neat idea of stocking only RES and another predator. I am not sure of which predator would be best. If you were in OH I would have you consider SMbass. HSB may also work good for you as a predator. At least you have very good control of the number of predators present. I think it would be a good idea to initially stock two or three sizes of RES; 1"-1.5"; 2"-4", and some 5"-7". This way you will have several year class right away and you can start fishing / harvesting quicker.
Snails can be introduced into your pond as forage items. I recommend you chose at least two or three different species. Start with Physella, Physa, and Gyraulus or Amnicola. Physa and Physella have the thinnest shells. Stay away from the snails with the thickest shells such as Pleurocera, Elimia, Valvata, and Helisoma. Helisoma is a very common snail but be sure RES will readily eat them before stocking Helisoma.
Crayfish may be another good item to stock as forage.
Without Bgill present, the invertebrate community should provide an abundance of additional natural food sources for the RES. Without bgill the larger forms of zooplankton should also do well and help to keep your water filtered and clearer so the RES, as sight feeders, can more easily spot the snails as forage items.
