Do the Baseline Expectations include requirements for endpoints in metadata?
There are no specific requirements for endpoints as part of the Baseline Expectations. However, InCommon Operations has requirements and recommendations for endpoints documented in the wiki, https://spaces.at.internet2.edu/x/IImKAQ
Do you have examples of XML syntax for placing the required elements in metadata?
You should not need to understand XML syntax for this purpose. An InCommon site administrator can edit and update metadata using the Federation Manager web interface. Information about each element in metadata, include those that are part of Baseline, is also available on the wiki.