Has anyone had experience with this? Our winters can be severe. I was thinking that it might help if I planted the figs along our south facing brick wall. Do I need two plants to get fruit?
You did well planting them against the south wall, however your zone is way too cold for the figs to be planted outside.
I can't even leave the figs unprotected in zone 6. With espalier you need all the wood to survive, unfortunately in any zone colder than zone 8 where temperatures drop below 20, you'll end up with the wood dying.
Only one tree is needed for fruit production with the common fig varieties.
If I were you, I would dig the trees out and plant them in a container, and place them in a cool garage. That's the only way you'll get fruit.
Get a large container and you can have your Fig tree.
Then you can bring it inside for the winter.
If you like figs, it works.