No reason to flame you for a theory, thats why threads exist Jimbei and Luffy came to the crimescene to ring the bell for a new era and Luffy alrdy knew when Law told him about Kaidou except that Law doesnt know about Big Mom (i think).
I don't know, have Law mentioned that Whitebeard is gone? It was said, that Reyleigh was a strict mentor and Luffy didn't get any news from the rest of the world.
And he only asked if Ace was dead, since he collapsed a few moments later. I still wonder :S