Aeration, from the bottom up, creates vertical currents, effectively mixing your water column. As well, aeration adds much needed oxygen to lower levels of a pond.
A fountain usually drafts shallow and is designed for aesthetic appeal.
If you want to stock bass, build the food chain first. Use fathead minnows and bluegill. Allow them some time to become established, then stock bass.
I like fingerlings...they grow up in your environment and become conditioned to what your pond is, and has.
Numbers of fish are determined by your goals, and your pond situation.
