Forum:Magical Dimension Question

I was wondering, if I use magical dimension and tribute one of my face down cards with a flip effect like old vindictive magician or Gravekeeper's Guard, will the effect be activated before the monster gets sent to the graveyard?

I also have another question, could I attack with a monster like for example Breaker the Magical Warrior and during the battle phase activate magical dimension, and then special summon a monster like say Dark Magician, could I then attack with the Dark Magician?