Hi M-Held,
thanks for your feedback and our question. First a disclaimer: I'm not working for Microsoft and I'm not a licensing expert. The writing was based on my participation in the private preview. Based on the docs that are currently available I would read it like you did. Having an org configured (for example to allow) access would not result in a P1 license requirements. But if you further customize the settings to only allow a single application or user for this org you would need an AAD P1 license. The other requirement is not a new one to the B2B collab space. If we provide Premium features like MFA this will require a P1 license. So, it is logical to also "enforce" this for B2B direct connect. Maybe I get some answers and I can come back with an update.
Ciao Marco