And it seems the solution in the docs only shows multiple values per one key. What is the recommended method (if one exists) to send both? Something like this but probably not this?
One of the advantages of resources.GetRemote is error checking, where you can choose to either ignore errors (with warnf) or fail the build (with errorf or erroridf).
{{ $data := "" }}
{{ $u := "https://example.org/books.json" }}
{{ with resources.GetRemote $u }}
{{ with .Err }}
{{ errorf "%s" . }}
{{ else }}
{{ $data = . | transform.Unmarshal }}
{{ end }}
{{ else }}
{{ errorf "Unable to get remote resource %q" $u }}
{{ end }}