EPEL is under the Fedora project umbrella meaning it uses resources such as RH bugzilla for bugs, package requests, etc
The packages you mentioned are part of EPEL and not part of RHEL proper. Packages in EPEL are not going to be pulled into the core CentOS distro -- the only place you *might* see overlap would be in the CentOS extras repo, but for packages such as these I wouldn't expect them to be in CentOS extras either.
-Jeff