Many thank to @DianeFranklin80 for sharing a photo from the alternative ending of Bill and Ted’s Excellent Adventure on twitter. Diane Franklin played Princess Elizabeth in the film.
A description of the alternative ending posted in an article in The Hollywood Reporter is below.
Winter points out that the ending for Bill & Ted that was originally shot was “completely different and really bad: it’s me and Keanu sitting on Bernie Casey’s desk, literally presenting a really boring history lesson to a small, ugly suburban classroom. So it’s visually really ugly. It had no scale at all. It was an audience of, like, nine, and there wasn’t much room for interplay. And then we go to the prom with our princesses. There are shots on the internet of us from that scene where we’re wearing tuxedos with shorts. But it just didn’t play. We knew while we were filming that ending that it was a dud.”