To answer the prompt (which no one else has), my first suggestion would be to not donate at all. Although the current situation is not good, I don't think Steemit will go to hell in a handbasket as quickly as you predict (unless we wake up tomorrow and some other blockchain has completed a better ecosystem that included a fully functional blogging-for-rewards platform). You may yet have a chance to salvage part of your investment instead of completely writing it off. Now if you had invested no money at all into Steemit, then a donation would make more sense.

Nevertheless I'll also assume that you still insist on donating the funds, in which case suggestion #2 would be to look at the delegators who tried to help out your cause. They would be the most loyal of your friends and most worthy of receiving donations. Divide the donations as you see fit amongst those people.