1: I am running the newest version of cura, this is my customized gcode, but the original code is no different ABL wise.
2: The only thing I have changed is the build plate, I am using this one here.
3: I am running firmware 1.7 something, (I can't check now because I am printing, and I will edit this post with the proper firmware) and I haven't tried updating it, I am afraid I will mess up because all I have is a mac.
4: Yes, and it works fine, but I feel that I should be utilizing the ABL. Or maybe if it ain't broke don't fix it. 😁
Hope this helps!