Make sure to read up on if there is an Apple version of Google's SafetyNet Attestation API and how that might affect your strategy with these physical handsets.
Also, look into the iPhone's UDID - it appears quite complicated to change it:
https://www.reddit.com/r/pokemongob...tructions_how_to_reset_your_iphone_device_id/
It looks like you can rotate it to a new one, but not sure how you would go about getting an old one back (ie it would be fairly suspicious if your account kept logging in from fresh UDIDs each time...)
Obviously the simplest way around it is to just have a 1:1 device to account ratio if it was a long term strategy (even then if you wanted to run 1,000 accounts, that's $100k in used iPhones) and it seems like your plan is to create many accounts per device which seems obviously problematic with this approach.
Perhaps because you are only planning to create one off accounts, getting a fresh UDID each time might not be a problem?
Will be interested to see if you find any way around that! So make sure to post if you find something!