I think your plugin indeed is a key plugin for a QA-SO feels.
I would recommend you to rename your plugin tho. -QA is too general. What your plugin does is more specific : posts voting and sorting. Be clear : this is great and it’s complementary to other plugins you rightly cite, which together provide multiple bricks to pick as needed to get closer to a QA feels.
See also :
[1] : Plugin which turns discourse into stackoverflow