Hey, I have a similar name-plate setup in one of my projects and the check box didn’t do anything for me either, however calling it in a function using http://blueprintue.com/view/xDK1i_Wc/ and calling that function on begin play seems to work perfectly fine for setting it invisible to self, I guess also by using that you could set all other nameplates invisible to just yourself as well.
As for the render distance of nameplates and floating combat text, I guess a large sphere component around the actor?