Following along. FYI, my pond is 7 yrs old now. One ac, surrounded by trees, so I get the leaves. I run a feeder, but not heavily. I don’t think my pond is as heavily stocked as the OP because I lost a lot when original stocking took place. I’m getting some gunk on the bottom, both from soil coming in, but mostly from leaves. Pond will freeze over, but not for long. (3 to 4 weeks).
So no fish kills yet. OP you may have some time to decide.
I’m too far from the barn for running air or electric. Considering solar for aeration, but haven’t pulled the trigger yet.
Nope, you can bury poly line to the pond. I'd use 1 1/4" dia to compensate for the length of run and to minimize any chance of water condensing and plugging the line due to your soil topography. Solar will need sun all day long, How many trees do you want to cut down to get sun to the panels? Batteries will be needed to run the compressor at night. I'll bet you it will cost you way more $$ to run solar than to run a line back there.