To separate this a lil step by step:
For the puffer's I'd breed snails (whichever kind you have available in your tank, just set them separated in a mini tank to breed, they naturally do this in 100's and 100's of eggs.
For the Betta I'd feed Bloodworms ideally with a mix of medium sized good quality pellets.
The "regular" shrimp I'd not recommend for food source (only the brine shrimps) simply because you gotta consider a good quality shrimp (Red Cherry etc) will be what about $2.5-3 per shrimp, you'd need to have at least a gang of 20 to start breeding and hopefully will breed enough quickly to supply enough food. Then you'd need a 10g set up for them, properly done so they actually will breed etc etc.....Snails & Bloodworms are just far easier. And my Betta lives in the shrimp farm and doesn't even touch them so....