It could be considered to be a verbal contract, but even in that case, I think the encumbrance would lie on Ned, who is the one who made the promises. He certainly did not do them as an "official representative" of Steemit Inc, as that would have required formality, as you say.

Therefore, even in that case, the strings would be attached to the proceeds of the sale, and Ned should dedicate them to development. Justin just paid good money for his STEEM like every other investor.