Here I am already. 
After some testing, using the engine test procedure I was able to get the T200s to move a little. They move little and badly, to start them it is useful to help them by rotating the propellers. It almost seems like they have little power available. They also activate when I try on channels 3 and 4 and with 1 and 3 as it should be (being connected to ‘main’ ports 1 and 3 of the pixhawk).
It’s all a mystery to me.
Could it be a problem with cables not being connected well? Could it be a problem with the ESCs (I inserted them in a heat shrinkable sheath and I wouldn’t want to have damaged them while I heated the sheath with the hairdryer)?
Here two videos explaining the issue:
Thanks again for your patience and help!