There's one new crewmate we heard about. A guy named Aokiji.
During the conversation, Blackbeard compared Aokiji to Shiryuu, who was also part of marines. We can safely assume Shiryuu is one of those 10 captains. So, comparing Aokiji to Shiryuu should be an obvious hint.
My only problem is the fact Aokiji joined Blackbeard shouldn't be so wide spread but maybe the fact BB has 10 captains is more known than that Aokiji is one of them. Dofla did say he has heard some nasty rumors. And ultimately, I don't see Aokiji joining BB as anything else than a member equal to his other starting crewmen.
I can't see Kuzan having joined the BB's and being an official "Titan Captain" without it being more widespread and well know.
I think the comparison between Kuzan and Shiliew is purely based on their WG pasts and not on their current status.
Kuzan is most likely doing some kind of business with the BB's, or has at least pushed to do so, leading to Burgess' comment about not trusting him because of his past, with Teach then alluding to him being shipmates with another former WG official.