Your are not allowed to use the CAL for ONprem Skype, SharePoint only for Exchange in Hybrid mode
Read!!! MS Product Terms http://www.microsoftvolumelicensing.com/DocumentSearch.aspx?Mode=3&DocumentTypeId=53,
2.2 Extended Use Rights for Microsoft 365 E3/E5
2.2.1 Office Servers
Each Licensed User assigned a Microsoft 365 E3/E5 User SL may:
- install any number of copies of the following server software on any Server dedicated to Customer’s use: Exchange Server, SharePoint Server, and Skype for Business Server; and
- access to the above server software is exclusive to those users assigned a Microsoft 365 E3/E5 User SL or External Users.
This provision does not apply to User SLs acquired under the Microsoft Cloud Agreement.
CSP = Microsoft Cloud Agreement: Microsoft Cloud Agreement is used in the Cloud Solution Provider program.