I don't see how Don Q would be a Blackbeard Pirate. He's been prepping for the New Age since Shabody, hell, you could even say since he killed Bellamy. I don't think he would join Blackbeard, but hey, that's me.
In regards to the whole Jinbei vs. Hancock thing, I don't really see Jinbei leaving FI now that WB isn't protecting it. And for Hancock, well, two King Haki users on the same crew? :/
just my thoughts.
You could argue the same about BB's crew. The amount of level 6 prisoners he has. You would imagine Luffy would need equally talented crew members by the end, so having a warlord or a King Haki user doesn't seem that odd IMO.