Considering that there isn't a move tutor in X&Y for Heal Bell and Pokebank is down, is it possible that Eevee can be bred Heal Bell, e.g. by a Smeargle?
No.
Eevee learns Heal Bell only by Move Tutor. If a Pokémon learns a move exclusively via Move Tutor the move cannot be bred.
Source: http://bulbapedia.bulbagarden.net/wiki/Heal_Bell_(move)
http://www.serebii.net/games/breed.shtml
Hope I helped :)
Nope. Bulbapedia doesn't have it as one of the moves that can be passed on via breeding and Serebii puts it's method as move tutor in B2W2