Ephont's CE works with Missles, Flamethrower, Grenades, etc. Only with Fringer followers though, against targets with Accurate Shot, so it's not really all that handy.

I don't know about your SS question. If I had to guess I'd say no, but I wouldn't be surprised if it went the other way.

Ephant Mon's CE does not override the "may not be targetted" clause of Superstealth.