There was never going to be any evidence to be found about what happened to Dr Ford, unless the two other people in the room confessed.
She knew that when she went in to testify. It was her word vs his.
Deborah Ramirez's claim came from other classmates talking about how they remember hearing about that incident around the time it happened. Not from her.
She was then contacted about it, and confirmed it. That's not evidence, but
Not sure about the third woman.