I think all documentation was clear in explaining individual concepts. Since there are a few different mechanisms to implement REST services, the missing bit for me was that I didn’t have to choose just one of those mechanisms, but that I could use them in combination to achieve my goal. In my case the Content REST API  provided 99% of what I needed already, which I didn’t want to recreate to achieve the missing 1% (the link). The solution came once I realized only the 1% had to be implemented in Plain JAX-RS services  while still benefiting from existing functionality that is already there out-of-the-box.
This might not be the cleanest solution because I have to make two calls from the client to get the data I require, but in my use case that is an acceptable compromise.