Hi,
you cannot use a regular Office MAK nor KMSclient for TS/RDS. These pkeys will not be accepted.
You must use the specific TS/RDS pkey for Office on TS/RDS.
Office products (and Windows too) are activated on a per-installation basis. It doesn't matter how many users logon to the machine, it is the installation which is activated, not the per-user aspect.
So, in your scenario, you (as the TS/RDS admin) would install and activate Office on the TS/RDS server, once.
Then all TS/RDS users can use Office. TS/RDS users are not asked to activate (they would not have permissions to do so, in most cases)..
Office is licensed on a per-device basis, not a per-user basis.
So, in your scenario, each user pc must be licensed for Office - it doesn't matter how many users there are, nor how many users are using TS/RDS concurrently.
Every pc which can use Office (either natively or via TS/RDS) must be entitled with an Office license.
Office via TS/RDS doesn't save you any Office licenses, because every device must be licensed anyway.
Note that the TS/RDS server itself, does not require an Office entitlement if it is only hosting TS/RDS sessions.
If the server is executing any Office components, not used for TS/RDS (e.g. a document rendering engine or some similar thing where Office components are in use by services/automation on the server) then the server does need an Office license.