Typically additional attributes would need to be configured aka "released" by the IdP on a per-SP basis. I've also never heard of any specific server requirements when interfacing with Shibboleth. SAML is a standard and any generic library that supports SAML (e.g SimpleSAMLphp, saml2-js) can, in theory, work with Shibboleth. It sounds like there are other organizational/operational restrictions or requirements in place.