These positions were meant as a way for those who don't match but desire to go into a primary field to do something productive during their "gap year" while providing care to underserved areas, not as a long term option for those not desiring to pursue residency. At least that's what the Missouri legislator that spoke to my class said about the program.
No, because physicians don't have to have completed residency to practice independently. If you want to be a GP, then as far as I know you just have to pass Step 3 and you can practice independently. Problem is that no insurance companies or government entities will reimburse you, so you'd pretty much be limited to a cash only practice. While it's possible and I have seen 1 or 2 physicians who were GPs that didn't do residency, if you want to practice clinical medicine you're going to have to do a residency.
Others can correct me if I'm wrong in their state or if laws have changed, but I do know that there was a GP that never did residency in the town I grew up in.