Drop ship a preconfigured iPad to elderly in-laws?
To answer my own question - the answer is no, the SSID/MAC address of the base station is not paired up. Thank you all for the advise, the plan worked. Shipper at 100% power and received at 20%, auto-connected to WiFi for us to call and do the rest!
You can, however use mobile device management to automate add a large menu of options on both iOS, macOS, iPadOS, tvOS, watchOS.

https://developer.apple.com/documentation/devicemanagement/profile-specific_payload_keys

Wifi SSID is one that’s very common, but instead of your relatives needing to know how to enter WiFi, they need to be shown how to install a profile or remove one if things change.