[Samba] Windows 2012 server as a member?

[Robert Wooden]

It has become necessary to have a W2012 server on my local lan.

I have an existing Samba 4 (Ubuntu) domain with two controllers, a (Ubuntu)
member server and a few W10 workstations.

If I am reading the wiki correctly "Joining a Windows Client or Server to a
Domain" page indicates Windows clients or "servers" and the "server"
portion of the lists include W2012. Now, I see no reason why this "server"
cannot act in a similar manner as my Ubuntu member server, as a client
joined to the domain to share the file access needed? (The need comes
because the preparatory program needed runs on Windows Access Database.
Access being the database program part of "Office" and as current versions
of "Office" may not run well on WINE then, I need a Windows 2012 Server
machine.)

So, am I incorrect and this machine will need to be a domain controller?
Or, can, like I am wanting to do, simply it be joined to the domain as a
member server only? (I'll repeat here that I do not want to use W2012 as a
domain controller only as member server. )

Am I wrong or is it a necessity that 2012 HAS to be joined as a domain
controller?

Thoughts or questions?
-- 
Thank you.

Bob Wooden