Am I allowed to set a stop order that might possibly execute tomorrow?
Psak I was given that all orders to buy or sell need to be suspended
Is one allowed to daven for personal bakashos on YT?
Good question. Many kehillos that, for example, say the tefillah by duchening on Yom tov skip it on shabbos. On the other hand we don't say bakashos in shemonah esrei.
Do they use a distributor?
Who, amazon? I think the real question is who owns the food while it's being stored by Amazon, the seller or Amazon. And if the seller, do I need to be choshesh he's Jewish. I don't see any reason to be machmir unless you know he is.