The common pill shaped minnow traps with the two inverted cones on either end work well for creek use. Make sure you get the "minnow" trap and not the crawdad trap. They look identical, but the crawdad trap has larger holes in the ends of the cones. My pill shaped "crawdad" trap rarely keeps a fish due to the larger hole, but does great for the craws. The cloverleaf traps in Rod's second link work really well for small creek fish and craws, but better for the fish. A similar trap to the cloverleaf called a "Z" trap has a good reputation too.
I think your goal should be to get a reproducing forage fish population going asap, as I think you know. You will be hard pressed to trap enough creek fish to merely feed the LMB. My creek harbors a large variety of pan fish. Mostly GSF, some BG, and mixed/hybrids of GSF & BG. The creek also has some very vibrant sunfish, maybe long-ears or red-breasted and a variety of minnows. Like you, I sampled my creek and tried to ID it's inhabitants and found that the minnows were not suited for pond life and that I was not fond of transplanting miscellaneous panfish into a pond that I wanted more control of with regards to my goals. It was a fun and informative venture, however. Your options may differ since you have a constant throughput of water.
I suspect with a small LMB pond, you will need plenty of forage fish and that the LMB will produce their own to cannibalize. Your pond will produce copious amount of LMB, but without routine harvesting of the LMB...they will overpopulate quickly and stunt. Expect to remove many LMB at the 10-14" range each year. This will remove many hungry mouths and leave more food for the remaining LMB to grow on.
Look into Relative Weights of LMB. This will help you determine if a caught fish is growing well or if it is lacking in food. This will also help to decide which fish to cull and which to return to the pond.
