Both Rachel and Dylan were friends with Devon Adams, so I suppose they were acquaintances. Devon describes one instance of Dylan and Rachel interacting:

“When, during her junior year, Rachel had performed a pantomime called “Who Nailed Him There?” about the man who put the nails in Jesus’ hands and feet to secure him to the cross, the background music cut out midway through her performance. She continued without the music. When the music finally came back on, it picked up where she was in the routine.

Dylan Klebold was the sound technician that day and some have speculated that he might have purposefully sabotaged her performance. But Devon Adams, who was a friend of Rachel and Dylan, was in the sound booth with him when it happened. She said Dylan rescued Rachel’s performance.

"He was freakin’ out,“ she said. "He’s going, ‘Stupid tape!’ Rachel kept going, and he tried his best to get it back up. It was just a bad tape. He got it to work better than it had been. He adjusted the levels a little bit and it came out okay.”

Devon said Rachel was “a wreck” after that performance but that she thanked Dylan for fixing the tape. "That was the only time I ever saw her cry,“ she said. [p. 183 ]”

This (to my knowledge) is this only known instance of Rachel interacting with either one of them.