Yes, both species have to be collected fro the wild.
Bluntnose minnows reach slightly larger sizes than FHM and are a bit more tolerant of predation. Spotfin shiners are even more predation tolerant, but unlike GSH, they only top out around 4" so they don't get to sizes too big for predators to eat. They also don't compete as much for food sources with sunfish as GSH do.
As far as your plans for the stream, it is an awful lot of work for little to no return IMO. If you got a burning desire to experiment, go for it but it's not needed. In all likelihood, your creek chubs will be eaten in short order no matter how many you stock. 20, 200 or 2000...
