I looked into the open source anvil code for stripe, it looks like only email is supported in the anvil implementation of the stripe API interface.
(You may be correct that stripe supports other information, but anvil is not passing it to stripe)
The only way around this would probably be to use the anvil HTTP requests library to interact directly with stripe yourself, using the stripe API documentation, stripe account, and API key, but I have no further insights as to how difficult that would be.
You can use the full Python Stripe library on the server, as long as you pass the right parameter in the client when getting the Stripe token from the user: Anvil Docs | Using Stripe's Python API