2) How wide and deep was the creek bed normally in 1863? I visited the area around the remains of the stone bridge and the creek bed looked about 20 something feet deep and about 20 yards across. Does that sound right?
-- I wasn't there in 1863 (in spite of what some assume) but when we were doing one of the archeological studies I stood beside a tree on the north bank (which was about 22 feet above the creek bed) and noticed flotsom in the branches of the tree (which were about 12 feet above my head); this indicates that the creek can be 40' deep at high flood; and I have seen it running nearly 3/4-mile wide at that stage (nearly covering the modern bridge). To answer your question, I think: In my twelve years on the battlefield, the creek ran "ankle deep" most of the time; but there were approximately 20 days a year when it was knee deep; and another 10 days a year when it was waist deep; and another 4 days a year when it was bank to bank (i.e. 20' deep); five times in the twelve years it was WAY out of its banks -- but that typically lasted only from 4 hours to a max of 36 hours.
3) Were the smaller fords usable at the time of the battle or was the water too high?
--Since the Cherokee regiments were guarding the two down-stream fords and the Creek regiments were guarding the three upstream fords, one must assume that they were fordable. Most of the Union troops fought their way through the creek to gain the south bank.