Just in case anyone else runs into a similar problem, I was looking at the wrong api urls to get what I needed.
I needed to be getting JSON from the topic data, rather than category or post. Most everything is working now.
I'm pretty sure I set something up wrong here, and just realizing it. I just spotted that all mentions, and RSS feeds for my site appear to point to the IP of my site, instead of the URL. See here. Any ideas what could be causing this?
url within config.json.