I always run in stereo to the PA so my delays and rotary effect are presented in the right way. Not usually panned hard L/R, but stereo wherever the sound person puts me in the mix.
If you're running master mono you only need a single feed to the PA.
I think your setup is good, but agree you don't need speaker cables to your powered monitors since all of the big current is happening at the monitor.
Have a great show!