Why would any cast member (including the captain)have "information" that would not be divulged at shareholders meetings and the like, particularly in a publicly traded corporation? Major initiatives, like commiting to spend $500+ million on a new ship will will not escape Wall Street for more than a second. The rank and file employees are not "need to know" and I expect preliminary plans would not be exposed to them, before they are decided by Disney executive staff. That is just not how corporations are run.
Like I said, if a contract with a shipyard to build the next ship were signed, it would be public knowledge within the hour of signing.
All Disney has announced is they have a concept for their next ships, nothing more. Until Disney makes an announcement, all we can do is speculate, dream, rumormonger, etc.