I have a feeling that the EOS/Steem2 won't airdrop to steemit holders. If anything it would airdrop to EOS holders and early adopters of the new platform.
But more than anything, I don't think Dan will be the main developer of Steem2.
I think his main criticism against Steemit is the centralization and the strange synergy between Steemit Inc.(Ned) and the whales.
So I think it's more likely that he will encourage people on the new EOS Blockchains to make the best new social media without a clear lead developer and then Dan could be the advisor if they need anything.
So something like the Bitshares core developer team would emerge for the Steem2 and they probably would feel that they don't owe the old Steemit anything.
Just my 2 cents and speculation.