In a debug console I've found out that all created VNSequenceRequestHandlers use single _VNGlobalSession object, which, as I understand, control request queue...

Well, I had a call with Apple Support team regarding this question. Yes, they approved - we can just initiate the process. As of now we implemented in our app this approach: the user just get prompted to the email form where he writes his email and the data regarding his account (identifier) is attached to this email. Later, the support team just answers his call.

For me, the "sort by name" on the Project identity helped - after applying the sort, the Products folder appeared in the list

Hello! Have you figured out how to reset the user’s choice?