Welcome to the Asana Community Forum @james.liebman!
If you have a paid Asana Team you should be able to reappoint another member as the billing owner: https://asana.com/guide/help/premium/billing#gl-billing
If you upgrade a specific team, only that particular team will be considered on a paid plan. The rest of the organization and the other teams will remain on the Basic version of Asana with the option to upgrade in the future.
In your case if you want to work with a lot of guests maybe having an Org can be convenient as well.
Here is a great overview on the pricing structure:
In terms of rules since you created them this should be considered.
Because when you are guest you have a lot less possibilities.
You can also reach out to support@asana.com so they can assist with changing the billing owner or if you have specific questions about your plan etc.
I hope that helps