Score order for untuned percussion?

I don't know how "definitive" an answer there will be, since I imagine there is not a lot of standardization here. But FWIW, my edition of Kennan/Grantham "Techniques of Orchestration" says that aside from putting timpani first, there really is no standard, but from a practical perspective, composers would be advised to think through how many players will be needed and who would play which parts. It is rarely one per part - the same person who plays the wood blocks might play the bongos if they are not needed at the same time. And then the ordering of the instruments would be chosen so that instruments that make to be played by the same player are grouped together. And this will obviously lead to a different order for each score.