The "using Twitter to hold drafts for someone else with the password" thing doesn't really work as well as it does with gmail or a gazillion other websites that could be used for that purpose.

The other interesting thing would be the IP access log, if there is one, showing the network address being used to access the account at various points in time.

For example, with respect to any particular message on Twitter, team Trump could claim that someone else wrote it or that he doesn't remember who wrote it (or by asking the witness how they know Trump wrote a particular Tweet instead of someone else), but nailing it down to a particular IP address would certainly narrow the circle of persons who would have had to have been there to do it.

Can you imagine the data storage requirements to even keep that stuff around for several years?

If they used a VPN?