Yes these are annoying bugs, we all agree, but ATM we have other more pressing concerns to deal with. we will get around it though. The zoom glitch can be solved by turning off widescreen fov in assist settings.
I don't think so, there was a zoom bug for weapons like M9 wich the sight were messed, i fixed this while back.
I can see if the player isnt in zoom, if so set the fov(btw thats how I fixed m9 prob), gonna try it later, it its harder to replicate teh bug

about lean thing, its not a bug, Lean is replicated to the server and to other clients, so if the server says you were at X position(while you can see you are at Y pos), server will shot at X pos.