Hybrid Config - Moved all mailboxes to Office 365 - now what?

Hi,

We have an Exchange 2010 Server in a Hybrid configuration with Office 365 (we are using dirsync).  I moved all active mailboxes to Office 365.  Initially I assumed I could just decommission the Exchange server, but now I'm wondering if I could just stand up the free Exchange 2013 Hybrid Edition and use it for administrative tasks.

Here's my question(s):

For people who do end up standing up the Exchange Hybrid Edition which does not allow hosting of on-premises mailboxes, how do you add new mailboxes?  Currently, I create a mailbox on-Premise, then move it up to Office 365.  Would this be violating the Hybrid license (or do they even allow this functionality with the Hybrid license)?

I appreciate your time.

Thanks,
John