Clarification on SSL renewal.

When generating a key via the term using "openssl genrsa -out domain.key 2048" does the actual name of "domain.key" and "domain.csr" have any relevance aside from providing an identifiable label?

No.

Does the location of the generated key and csr file matter, can I say make a temp directory, generate my keys in there and then move them to the appropriate directory before making the support request to install them?

The location of the generated files doesn't matter - just let us know where they are when you open your ticket.

Is there any way to determine which currently existing key points to which domain, I don't think i need this information for anything but I have a deep curiosity about this for some reason.

You can get the domain for your certificate with:

openssl x509 -in whatever.cert -noout -subject

You can then determine which private key matches that certificate by following these instructions: Verifying that a Private Key Matches a Certificate

Hope that helps!