Wow, Mark. That's a big undertaking.
I had a brochure from the Fort Check-In desk with group camping rates and rental information on cots/tents. I took a picture and posted it in this thread a couple years ago:
https://www.disboards.com/threads/camping-gear-rentals.3331588/#post-52311701
See post #3.
In case Photobucket decides to *poof* my account any time soon, the phone number in that brochure for group camping is 407-939-7807. I don't know if that's still a good number but it's a place to start and if it's not the right place, hopefully they can get you where you need to go. At the time of the brochure, tent rentals were $30 a night, cots $5 a night, and the camping fee was $10 per person per night. The tent pix I show had 3 cots in them but that's really too tight so figure two people per tent to have room to stand up and a bag for each person.
Good luck and let us know how it turns out.
Bama Ed
PS - my first trip EVER to Fort Wilderness was decades ago in the group camping area, Creekside Meadow. I thought the place (WDW, Fort Wilderness, Creekside Meadow, [all of it]) was magical.