I just finished the Firebird 3.0 RC2 packages for CentOS 7.

Hope that it would help us to have more people testing this RC2.

The packages are in my Fedora Copr repository.

I will update it regulary so you could have Firebird 3.0 packages in CentOS 7.

Official Epel for CentOS 7 will stay with Firebird 2.5.