flareon: cloud nine.
sure, why not flame body that while sucks make a lot more sense?
It's not like it could make much use of cloud nine anyway; the reason golduck works in UU is because it can hit key members of weather teams, bar hail (who is really already disadvantaged due to blizzard's poor accuracy alone) for super effective damage and OHKO by running a simple set of Hydro Pump/Ice Beam/HP grass/filler (I.E. encore)
And flame body is actually not terrible.. sure flareon's not going to be living much anyway but still, if it manages to burn like... hitmonlee using CC, then good for you
The fact that it doesn't help against SE or EQ is bad though
Better question is how solar power would help espeon... Sucker punch and shadow sneak from stuff like spiritomb still OHKOes and it takes SR damage every turn. Wonderful.
Though chlorophyll leafon would kick soooo much ass; it already does even without an ability (I mean has anybody ever actually seen leaf guard activate? lol)