SO the short answer is No.
Unless the answer is Yes.
Confusing… yeah that’s why you’re asking to begin with.
Here’s what I would say if I were trying to sell it to you.
You don’t really need AD for 3 or 4 users… Maybe even 10 users.
If you only have a few users the things you need to do Active Directory for could be done manually… SO I’m guessing you’re asking “What things do you need Active Directory for?”
Well I’m glad you asked.
SO you need AD to manage authentication of Windows Resources like file shares and printers…
If there are only 3 or 4 users you can manage these items manually.
AND if you’re using Office 365 you can move your file shares to ODFB - or Sharepoint and solve half that equation. If you’re using Macs getting anything to work with printers is a whole other issue anyways.
If I had 10 or less users I would not consider having a server if Office 365 was part of my plan.
Hope this is helpful…
If you already have AD ( and some good switches) why not isolate the counseling center with VLans and ACLs? Are you separating the counseling center from your infrastructure for security or convenience?