In the company that I last flew for, we had two wet-leased TU-204s for a couple of years. One was RA-registered with Russian engines and the other was SU-registered with RB211s.
The crews were usually Ukrainian.
The astonishing thing was that they never ever ever went tech.
The only time was when the RB211 version had to have a windscreen change in the middle of the winter.
What I can tell you is that the absolute minimum crew was at least 5 and was usually around 11 (which is quite interesting when the aircraft concerned was a freighter)!!!!!!!!