Probably will find there is no good answer to this question, But Ill look for ideas or comments anyway.
I have a customer that wants office 365, they use 20 RDS connections for employees. They ordered 20 Office 365 licenses. After a bit of research, I found out that they need a volume license for Office 365, AND also must purchase a single Office Pro Plus Volume license in order to install on the RDS server (the Office 365 downloadable installer is a retail edition that will not install on RDS server). Now I get a call from customer and they need a company email, a shipping email and a contact email.
Turns out, to do this you must purchase full licenses and CANNOT add email address licenses only. Its either spend a few thousand a year to upgrade to E3 plan, or $600 to add 4 email addresses.
Do not buy Office Mid Size Volume license and if deploying to a RDS server, do your home work.
Now, anyone else run into this issue? Any ideas?