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.
the title more or less says everything.
I thought it would be enough to enable Guest handle in settings but Guests still cant post answers.
Any idea on that?
@Tobias-Teske in ACP, go to Manage > Categories, then select the category you want guests to be able to answer posts in, then go to Privileges, and give guests the "Reply" permission.
@PitaJ thank you