You don't know what we've been through...
In order for National Pokedex to be complete, none of the event Pokemon from any Generation are needed. And for Shiny Charm you only need a complete Nat Dex. So these Pokemon will not be needed:
Also I believe Reshiram and Zekrom are NOT Shiny locked in B2W2. I've seen some videos of people hunting them on youtube. It's a translated ROM so I can't say for certain: