Reyhan, Last of the Abzan and Hangarback Walker are in play each controlled by the same player and each have three +1/+1 counters on them. They both die somehow, let's say to a Wrath of God. Can you stack the triggers in such a way that uses Reyhan's ability to move the counters from Reyhan and Hangarback Walker to the newly created thopter tokens?
No. It doesn't matter how you stack the triggers. They will go onto the stack at the same time and when a spell or ability goes onto the stack, and it has 1 or more targets, those targets must be chosen at the time the ability goes onto the stack. In this case, Hangarback Walker's trigger will not have resolved yet (since it is still on the stack) so the thopters are not legal targets for Reyhan's ability.
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