I've found some mistakes on Hidden grotto's list.
Eevee can't be normally found on hidden grottos. That was a Hoax created when the game was launched. There is an event created by using funfest mission that can make you find any pokémon on hidden grottos. That special mission was used on japan to find any eevolutions, but you could use this event only on japanese Pokémon Center.
Butterfree is a White 2 exclusive pokémon, and Beedrill is a Black 2 exclusive pokemon.
About Jellicent, i think that is elevant to say that it is Male only on Black 2 and can be found every Monday, and it is Female Only on White 2 and can be found every Thursday.
Braviary can be found every Monday and Mandibuzz every Thursday
There is an in game trade on White 2 and black 2 that gives a Male eevee with hidden ability. The trade is on Castelia city, after beating elite four.