Only one could be considered "direct testimony". The others are purely hearsay witnesses and in a regular court proceeding would be thrown out the door.
I think all of this will go a long way in defeating Trump in 2020.
Once again, I'll argue that it will strengthen his case for re-election. People vote with their wallets. They may not be on FB or GCG but people are working and little Jimmy is getting that new computer game for Christmas. Most people vote for what is good for them.
According to ratings, the only people watching these hearings are already set in their thinking. No one has changed their mind.