Man oh man, I'm sorry to hear about this!
I did not have any issues with piping fish with my start up but I did churn up some old dead fish that were in pretty bad shape which scared me but nothing like what you have going on. From what I've read on your posts there were a lot of changes that happened in a relatively short period of time in your pond. First you treated the FA, then put in aeration, then got hot temps followed with a lot of cold rain and all of this pretty much back to back.

In my thinking, I don't think you really rushed the start up. In theory, you were probably turning the pond over long before Friday at least once a day especially when you hit the 10-12hr range on things. What I see is these temps followed by heavy rains were just at that time when you hit the 24hr run. If it were a result of the aeration I think the problem would have shown up sooner. The heavy rains possibly could have caused some or all of this whether or not aeration was in place or not.

Yes, it sucks but at the same token, you did manage to thin the population which was probably somewhere on that long list of things to do with the pond. So, if there is lemonade to be made out of lemons perhaps this may be a blessing in disguise. I know it's hard to see it that way but as long as some of your better fish survived it and some of the food supply survived it, you may end up with a healthier fishery in the end.

Hang in there and keep us posted on how this turns out.