Well.

That happened.

I'm rather hoping (too tired to put numbers on it, sorry) that Harry can summon a phoenix straight from the mirror-he never tested the claim that a phoenix only shows up once, after all...and now he's got the source of phoenixes right next to him. That's a gun that's just itching to fire.

"All your hallows combine" is fairly obvious, though the location of the stone is not entirely clear.