No stupid questions! Turns out the URL in the application was incorrect somehow in the application.
Instead of
/sap/saml2/sp/metadata?sap-client=100
it was using
/saml2/sp/metadata?sap-client=100
...and there is no alias in SICF for that. I manually browsed to that and was able to download the file.
I have provided the metadata.xml file to the ADFS folks....fingers crossed it works out-of-the-box.
I'll post new forum topics if I encounter problems, but I was curious if you an provide general advice : how would you recommend learning SAML2 at a slightly lower level of detail? The high level powerpoint description becomes somewhat useless once you get into the myriad of options that are available. The SAP documentation is nice, but for the most part I am just accepting defaults without understanding what they mean! I suppose if it works, I won't need to dig into it, but given that it is security/authentication I would prefer knowing a bit more.