However, I did not add any antifreeze (I have 4 gallons waiting to be added). How important is it to do this?
If you got all the water out of the pipe, or even enough water out to leave the rest below the frost line, the antifreeze isn’t even needed. It’s just extra extra insurance. It super easy to add 1/2 gal at each skimmer.
I have seven or so gizmos leftover, which I suppose I could put into he skimmer boxes to fill volume. Any reason to do that?
It will not hurt one bit. It might even help.
But I did not cap the shallow end returns while blowing to get all the air to the deep/far end? Do I have to worry? it seemed pretty dry
You should have gotten all the horizontal pipe water. With multiple openings it may struggle to force the water out the vertical pipes that go to the returns. Whatever you missed should be well below the frost line, and you may not have missed any because the cyclone is a beast. Add a gallon of antifreeze for the extra-extra insurance.
All good here.
No idea here. Hang tight for thoughts.
Should be fine once the 2 drain plugs (each, like you said

) are removed.
8) DE filter - I blew air through the filter initially as my multiport handle was stuck (I backwashed the DE before draining pool). Then I drained the filter by removing the plug as the bottom. Do I leave this plug open or sealed?
Plug it up
After draining filter I managed to get the multiport to recirculate. I also did not clean the DE filter as I had intended. Can this wait until spring?
yes it may. It’s a wet job and it’s windy as snot and 31 degrees out. BRRRR
9) Chlorine generators for pool
leave them in place. Those of us that bring them inside (

) only do so for their sleeping abilities. Any equipment can handle the elements just fine. If yours is going to be in the unheated house as the alternative, There isn’t much point to bringing It inside.
10) Autofills - I drained, removed the fluid masters. and blew out the lines, but I dont see a way to plug the compartments/tanks. I plugged the equalizer opening at the pool and spa, but the tanks can collect rain water and then freeze. How do I prevent that
Ice only expands about 10% and it does so upwards. A tank or open container is the perfect vessel to freeze with little concern. If you can get something in there to help, (empty milk jugs weighted down, pool noodles, etc) great. If not you should be fine as long as it’s not filled to the brim with rain water.
11) Open pipes - I have many open pipes at the equipment pad where my 4 pumps were connected. I brought all the pumps inside. I can either shrink wrap the holes next week, or pup the pumps back. Like with the chlorinators, I am not sure why it helps to bring the pumps off lien and into a cold room, versus leaving at the equipment pad.
You can DIY pipe caps with ziplock baggies and tape, you can get rubber winterizing plugs (the wingnut ones) at the hardware store for all the ends, or you can put the pumps back. All 3 will do fine by you.
I brought my equipment indoors. I didn’t like the prospect of it all sitting in a snow drift for up to a month. It could have done it, I know this. But the pump and SWG have electronics and it was easy for me to do.