Also, what are people's thoughts on Zoro, Nami/Sanji and Brooke being reported "dead"? False reports or just overconfidence?
These guys seem competent, I'm leaning towards a false report. Your theory is also interesting, but I got the feeling that Law's crew is not involved in this from the dialogue.
It seems Law is working alone, potentially there could be a team up with the SHs since he told them he too had something he needed to retrieve. I don't think Brown beard is dead, I will believe it when I see it.