Well if you want to do 1 gal id go 16 plants like GHwheels said. If 1 of each plant go in 5 gal. Personally i feel more small plants will always do better than few big ones. Also if a big plants shits out you lose alot. If a small one shits the bed you have many left. 1 gal pots are not crazy good for soil, maybe best choice is x8 3 gal pots of soil and get x2 of each of the 4 strains.
You can use the 5 gal it just means less room for error is all. Give them a go and by youre 2nd grow you'll know if you like them or want to try smaller.
Thanks for everything. Will x5 5gal bags fit in 4x4space comfortably or will it be cramed. Still waiting on bags to arrive in mail. That is last and final ques regarding set up. Once again thanks for the help and quick responses bro
4 for sure, 5 should be ok. Depends on how big/bushy they get but 5 shouldn't kill you. Anytime, @ me if you make a journal so i can watch along. Good luck and lets get that lb.