If the spring flow is cold and the volume is decent, if you decide against the HBG/HSB/CC fishery, you may want to consider a SMB as opposed to LMB fishery. Instead of BG, stock YP. You can then add a few WE and/or HSB as bonus fish. These fish would do far better in cooler waters as opposed to LMB/BG.
Those were pretty much my thoughts. I would probably skip the walleye and the hybrid sripers though. I wouldn't want a 15 pound monster walleye or whiper snacking on my one and two pound smallmouth. That would not make me happy.
With 100 yards of "creek" feeding from the spring to the pond you could try establish certain creek species of chubs or darters or whatever you like to add to the food chain. It may work in your situation.
