Daisy Eagan played Mary Lennox at six of eight performances, with one alternate (ibdb tells me her name is Kimberly Mahon) playing Mary at the Wednesday matinee and Thursday evening performances.
as for the OP, I think they boys deserved a special Tony, because I do think it is rewarding the role, not the actor, the way it was done. not that roles don't win awards normally, it's just not so transparent.
When I see the phrase "the ____ estate", I imagine a vast mansion in the country full of monocled men and high-collared women receiving letters about productions across the country and doing spit-takes at whatever they contain.
-Kad