Kodak quit making E-6 film a couple years ago, so it should be no surprise if they quit making the processing chemicals. Given that Fuji is the only manufacturer of E-6 film in the world now, I would think it would be better to use Fuji chemicals since you're using Fuji film.
Kodak's actual chemistry has been made by Champion for several years already, correct? *If* true, the announcement needn't mean anything about Champion's production for other customers like Arista. (I don't know if they actually make the Arista E-6 kits, but the point is, "not sold through Kodak any more" is not the same as "not made any more by the original source".)
Oh man...it's a good thing I started developing at home. There's several companies making E-6 kits. I used to get my stuff done at Toronto Imageworks...great place too.