Modern fig varieties require no pollination to set fruit, so only one tree is needed. 6b is a bit cold for an edible fig, though, and likely to be killed at least to the ground. Brown Turkey is often cited as more cold hardy, and there are others. It's been reported by some that figs can sprout from a well established root and produce a fall crop in the same year, but I haven't had success that way. Even here in 7b I tend to protect my trees so that I keep more wood and get a better crop. I think our rapid, dry temperature swings are harder on them than in other regions, though.
I'm interested in others' recommendations for hardiness, and their experiences. It would be nice to plant a couple trees in the yard that I didn't have to move or cover every year.
