Given Discourse is itself a web app, you may like to note that meta provides exactly this support to its product ecosystem and it appears to work extremely well.
Not sure what you mean here
Definitely
Take a look at:
The settings are very rich, and allow a lot of configuration, though I’ve never tried to switch off badges there is often the option to hide elements using CSS in any case.
Given it takes even a novice often less than half a day to install and configure Discourse, I’d give it a whirl on a VPS if I were you and see if you like it.