+1.
Minnows (fatheads or Shinners) will breed on any surface in the water throughout the summer provided the right conditions exsist. That means any structure in the form of old X-mas trees, aquatic plants, artificial cribs, rocks, and stumps/branches will allow for breeding surfaces and protection. The main focus should be on starting a forage base for the preds. A LMB would much rather eat 1-2 4" Golden shinners or bluegill per day than chasing down a dozen Fatheads.
Both fatheads, shinners and a panfish of some sort should be stocked before to many more preds are added. Fatheads will feed the bluegills which in turn will feed the bass. Golden Shinners are more expensive than fatheads, but will be the food of choice for the big preds. They readily breed in June under any vegitation and can eventually sustain a population that may only need to be stocked once or twice. Fatheads spawn all spring and summer, again provided with a little structure to lay eggs.
Try to avoid any Crappie in the first few years. Females can lay 60,000 eggs and they really only eat live foods (minnows) which makes Bluegills and Sunnies a better choice. They too are prolific breeders, but bass love them. If your friend is worried about to many gills, Hybrid Bluegills are a great small pond fish. The eat a variety of foods, 80% are males, and if they start to over-populate, they can be culled and fried. They also can get decent size that they put up a good fight on an Ultralight.
Channel Cats are a better pick over Bullheads. Channels rarely breed in small ponds since they need muddy banks with holes/caves to spawn. Bullheads on the other hand will spawn anywhere and once they get to be 4" or so, the bass stop eating them. They can be controlled with Northerns, but the Northern will also dominate the smaller bass. They slide right down there throut much easier than a spinny bullhead.
All this info. may sound confussing or discouraging, but fear not. Just a few tips on starting a pond off right. The preds will grow plenty fast as long as they have a steady food supply.
In closing, focus on getting some plants and structure in place so the little ones have spawn sites and can populate the pond. Once the forage in place, he can stock just about anything he wants.