I don't think they even need to ask. The way I read the terms, they already had it, so I think they are angling to put themselves in control unilaterally and one-up Twitter. Disney's terms have prohibition on "offensive" content, while Twitter's terms acknowledges you maybe exposed to offensive content. Twitter says others may use the content on other media and services:
> This license authorizes us to make your Content available to the rest of the world and to let others do the same. You agree that this license includes the right for Twitter to provide, promote, and improve the Services and to make Content submitted to or through the Services available to other companies, organizations or individuals for the syndication, broadcast, distribution, Retweet, promotion or publication of such Content on other media and services, subject to our terms and conditions for such Content use.
Absent another side agreement, I don't think Disney has more or less rights to content posted on Twitter by other users than any other user.
Thus, if they intend to launch a multi-million dollar commercial project using content posted to Twitter, they need to do some work to clear the rights.
The Twitter TOS allows Twitter to do stuff with user posted content. It doesn't allow Disney have unlimited rights to do stuff with content posted at @DisneyPlus by other Twitter users.
Absent licensing the content directly from Twitter, they could have asked for the rights for the few tweets they end up deciding to use. Thinking outloud -- I guess that wouldn't work if they wanted live stream tweets...
edit: fixed - somehow my third para said the opposite of what I meant
> This license authorizes us to make your Content available to the rest of the world and to let others do the same. You agree that this license includes the right for Twitter to provide, promote, and improve the Services and to make Content submitted to or through the Services available to other companies, organizations or individuals for the syndication, broadcast, distribution, Retweet, promotion or publication of such Content on other media and services, subject to our terms and conditions for such Content use.