Eevee doesn't evolve into Espeon/Umbreon even with full happiness("It looks really happy! It must love you a lot").
Usually when it has full happiness it evolves right in the next level.
Is that a bug or did you change the way it evolves into Espeon/Umbreon?
Other than that, this hack is really fun :)
nvm, I just got a moon stone from dear ol' mom and tested it...