I honestly can't recommend any one forum platform. I didn't mean to recommend Invision and I'm glad you didn't read it that way. Nothing against them, it's just my information is way out of date whether I liked them or not. The software was good. I was on their host/demo board and interacted with other customers and some people on the team. Nothing bad to say. I've never heard of humhub and Flarum, but again, my information is out of date.
I don't know much about blogging, micro or otherwise.