My whole project is ASL 2.0 licensed, hope this works well for you? I'm happy to go the donation / legal task path if needed. Note that I have ConnectionProvider implementation for Hibernate 3.6, 4.x, and 5.[0-1], but not for 5.2 - this is the point where a change was introduced in Hibernate. Let me know how you want to continue.

Also, I'm guessing that you're considering the integration for your 5.x branches only, is this correct?

And of course, I'll be able to help with choosing the default configuration values for Vibur where needed, etc.