1. 50/50 on that. They will likely tweak it slightly, but it will remain. The "Tennessee" wordmark that it is based on is definitely staying.
2. The T got smaller because of the models of helmet we wear that the vent holes could not be covered on. The T started shrinking a few years before the T was made square (was previously wider than it was tall) in the 2015 Nike transition.
3. Happening.
4. Maybe on a future throwback, but I don't expect the uniform designs in the five major sports to look significantly different than they did this year. UT is maintaining design control. Most fans won't notice a difference other than the manufacturer's logo.