4) I prefer a rifle with a little weight out front, or at least neutrally balanced. A butt heavy gun sucks for offhand.
This do make things easier. The real lightweights are tough to shoot offhand, I find a medium weight ( 8 lb) rifle with a mag contour barrel about the easiest.
And personally speaking, I don't like a sling on a rifle for offhand shooting, and don't like to shoot all wrapped up in a sling either...JMHO