We raise a few English Angoras, in the central part of Oklahoma.
We just added AC this summer, before that they were in a barn that is pretty well insulated.......so it stayed a good 10 degrees cooler then the outside temperature.
It probably got up to about 90 in there. They did ok, we kept them clipped, and used ice bottles and fans. But it is hard on them.
Definitely no breeding during the Summer, try not to stress them, and keep them on their feed. A big thing is making sure they have cool water at all times. Those bottles heat up fast. We provide bowls of water in their cage, as well as water bottles....we've found the tend to drink more that way.
The first year we had rabbits we kept them in a shop that was not insulated, so it got HOT. We did lose two rabbits that year, although surprisingly all the Angoras made it. Still, it was so stressful on all of them, we were finally able to move them to the insulated barn. Even there it was hard to keep them cool, so we saved our pennies and this year we added an AC. No more stress on the bunnies, no more stress on us!