Old Domain/Forest still has SBS 2003 things in it, can I remove those?

Hi,

We recently setup Azure AD sync in our Windows 2016 network. We are getting notifications about some administrative templates from SBS 2003 not synchronizing to Azure.

They show up under MyBusiness -> SBSUsers I am pretty sure we no longer use any of this and I would rather just remove it if possible but is there any way to find orphaned and no longer used objects in your AD just so I can be sure that it's not in use?

Thanks.