This is a follow up to this post on stem export.
I found a way to export mono tracks to mono, with the processing. Actually I found 2 ways to do it.
If you freeze the track, and export it to stem without processing, the track will be exported with the committed processing on in the track.
On the other hand, if you send the track to a mono bus, exporting the bus without the processing will not prevent the processing of the track, just the bus.