A strange question...

[mehraban]

Sounds weirdly, but:
if body hotshoe is occupied with radiotrigger with its' own hot shoe, is it possible to use EVF in it?

 

[neuroanatomist]

Sounds weirdly, but:
if body hotshoe is occupied with radiotrigger with its' own hot shoe, is it possible to use EVF in it?

My guess would be no, unless Canon made the radio trigger. I have a vague recollection of trying an ST-E3-RT on top of a PocketWizard FlexTT5 and the Canon trigger didn't work.

 

[dcm]

I have an M3 with the EVF. Looking to upgrade to the M6II.

The Canon EVFs use a row of contacts at the front of the hot shoe mount for communication. Ken Rockwell has a nice image of the bottom of the EVF’s hot shoe mount, https://kenrockwell.com/canon/eos-m/evf-dc2.htm. The pins extend forward of the flash mount. It’s doubtful that any device passes these through.

 

[mehraban]

Yes, I've already had a look at that EVF, certainly it needs free hot shoe...

So - waiting for smth like M5 mkII... With normal EVF...