I've been calling, and have spent many hours on hold. I finally got through to a live person today, who told me that adding Genie+ in advance is not an option for an AP, nor is adding it for my entire trip. I'll have to add it on each day, which is no great hardship.
He also answered the other question I had. I purchased my AP in September, and everything in the app said my AP expires in September of 2022. Now, as you all know, in the past your AP would expire 1 year from first usage, not from the day you purchased. He confirmed that this was still the case, and the app showing September 2022 as my expiration was actually the expiration of the voucher. So if he knew his stuff, then I'm all set. Thanks for the help, my friends!