I work in music and audio post, and everyone I work with would love to be able to use Reaper (or Logic, or Nuendo) instead of Pro Tools, if Pro Tools didn’t have the post industry completely captured in the US.
Reaper is a world-class product, and the team could easily charge 10x as much for the pro licenses, and get it. Stick with Reaper.
There are alternative drum triggers for Linux, I’m sure. Even SPL makes a drum exchanger. There’s got to be one out there.
VMR shouldn’t be a problem to run, I just don’t know what the install process would look like.
I’m pretty sure Airwindows plugs are Linux compatible, probably Audio Obsession too.
In any case, Reaper’s stock plugins are awesome. My only real complaint about them is the EQ cramping in the hi-end, which is typical for stock plugins.