Assuming all the subpoenaed witnesses show up and testify...

[StarfishSaver]

6. It depends

Only some of them are entitled to claim executive privilege, which doesn't apply to every communication a president has, but only those communications he has with his executive staff.

For example, Bannon was not a government employee When he was communicating with Trump about January 6th so executive privilege would not prevent him from testifying. If Trump tried to invoke that and it got to court, I suspect a court would knock that down pretty quickly.

As for any employees who were actually part of Trump's staff at the time, I think it will be difficult to sustain such a defense, especially since the current administration would likely argue against it and their argument would carry significant weight - far more than any argument Trump would make.

Now, back to my question. Could you be more specific about what you think the committee would learn from these witnesses?