could I just replace those frames with new foundation??
Yes. You aren't losing anything at this point and removing those frames will kill the varroa that are concentrated in the drone cells.
My next concern is finding someone with mated queens at this time. I was told it's too early to order queens. Any suggestions?
You are living in the honey bee capital of the country. :-D South Georgia is where all the package bees come from so I'll bet you can find queens (especially since this spring has been so warm) But all you really need is a frame of eggs. There are plenty of drones around to mate with the queen your hive raises.
Also, I imagine that there are some swarms starting to fly in South Georgia. You might put out some swarm traps.
Angie, are both of your hives full of drone comb? It's very strange that both of your queens would go drone-only at the same time. Did your queens come from the same supplier at the same time? Have you had these queens since last spring?