I took a look at the leagues today to get a sense of how this will play out.
Div II has 2 demoting bots
Div III has 11 presumably demoting bots (7 are in 8th place, 2 in 7th, 2 in 6th) and 3 teams likely to go bot before the next season (1 of those is in 5th place, the others will be demoting anyway), plus 1 that might go bot in time, but I'm not certain and it will be demoting anyway.
There are 15 teams in Div. IV that are 21-0 going into the season finales:
IV.47 Dragonmasters ..........+850
IV.44 Griffin Shadows...........+826
IV.54 The Banana Bombs...... +824
IV.53 The Americans............+782
IV.1 Muppet Honey Badgers...+741
IV.27 GTZ........................+738
IV.58 Blazing Ninjas ............+710
IV.16 SkYz Da LiMiT.............+703
IV.29 Rum Ham .................+700
IV.18 Pyramid of Success......+667
IV.56 Smurf Village Smurfs ....+632
IV.22 N.C. State Wolfpack....+626
IV.55 Rockford .................+607
IV.4 Seachickens..............+600
IV.5 Beaufort Plankers........+556
I'll try to update that after tonight's games so we'll see how it looks. I didn't look for 1-loss teams at this point. I suppose more than 2 upsets are certainly possible and a 21-1 team could bot promote, too.