Is it possible to use ember-data with Glimmer, or is the full ember install required? If so how much of Ember core is it possible to ignore (e.g. just use components, no router, etc)?
Also if it isn't possible is there a library that would provide a JSONAPI implementation compatible with Glimmer?
I don't think it's possible to use ember-data without ember. You may want to keep track of the progress of the RFC for "Splitting Ember into packages". Specifically, it "enables people working on small, focused apps to start with a minimal, small core of Ember and only add more features as they are needed"
I'm not sure about the JSONAPI/Glimmer implementation, but I suggest starting with looking at standalone libraries in the implementation list.