As long as you’ve set up slashes in your kit …
… you can select notes and Cmd+Opt+Arrow them down into slashes:

Thanks Fred! Removing the other instruments from that 0 line makes it easier to move notes into slashes. I’m still looking for a way to easily take a rhythm from another staff, copy it into the drums and make it slashes. I’m happy to program a macro in keyboard maestro but it seems like the hangup is that I can’t transpose drum notes to a single pitch or find some other workaround to take multiple pitches and get their rhythms into this single line pitch/rhythm. I do this often enough that the time saved would be worth figuring out something. Anyone know if I’m missing a way to do this?
You could change your Percussion kit presentation type to Single-line instruments?
Then, you should be able to paste a melody into one of the instruments? Maybe a slashed one?
Thanks Daniel! That might be the easiest workaround yet. I copy the rhythm into a separate slashes staff and then copy from the slashes staff into my drum part. Not elegant but workable. Thanks!