Architecture Sanity Check

Regarding roles, you will have more of them for staff, especially to implement separation of duties (SOD). For B2B, are you planning to have any delegated administration among the trades? For example, if you configure Auth0 orgs for each of the trades, you may have one or a few roles. For customers, that would the role. These are just some cursory thoughts - as John mentioned, a session with experts will help you get to the strategy with all details taken into account. Please let me know if I can assist further or under a statement of work.