I went through the whole process again and it is now working correctly. I just learned that the steem plus button that is added to the steemit UI at the top logs me out, so it's possible I clicked that previously, expecting to get a menu but actually being logged out.

I just tested the GIF inserter. It's a bit buggy, but I did get a Gif inserted at least (for the first time since I've used this plugin and the previous version).

I don't have any plugins that I would think would interfere with steemit, no.