Can someone point me to a good resource on how (if permitted) I can make
appropriate compat(?) packages to allow for two major versions of the
same package to be available?
It works pretty much the same way as in Fedora. You can see if a -compat works or if it's a major version (library or otherwise) append the major version/soname to the package name. For instance, EL 7 had CMake 2.8 but there was a demand for version 3 so a cmake3 package was created.