Licensing question: Exchange Server SE for CSP M365 E3/E5 customers without Extended Use Rights

Does anyone have any information on licensing the new Exchange Server SE for customers who have M365/O365 E3/E5 purchased via CSP but do not have Extended Use Rights (i.e., no EA/EAS -> no on-prem Office server licenses included)?

Specifically:

Is it enough to license Exchange Server SE per node only, or
Do customers also need to purchase Exchange Server CALs per user (even if they already have M365 E3/E5)?

I’ve spoken with multiple licensing distributors and a Microsoft partner contact, but I still haven’t been able to get a definitive answer.

According to a comment from Jeremy Carlson and Microsoft’s licensing documentation, certain licenses appear to include "CAL-equivalency rights". Can anyone here confirm whether these CAL-equivalency rights cover access to Exchange Server SE in the CSP E3/E5 (no Extended Use Rights) scenario?