I can not tell you what to do. My advice is to watch the pond if you see bluegill spawning and coming to feeders and feel you have lots of fish no reason in my opinion to wait until fall on the bass. And vice versa if sumpin' happened then yes you dont want the bass in too early.
For my custoemrs who follow the plan bass grow well with spring stocking followitng oct-march forage stocking.
The shiners wil not "takeover" if you goal is good size bass- you want lots of em to ehlp bass growth. You are limited on threadfins shad options. The best chance for establishement and cheapest option is this srping with the "fry in a bag" program.
