Let me resume the experiences made until now.
First of all, I just developed a color negative film with Caffenol to wich I added just 5 ml of color developer from Tetenal already mixed with its three components. In this experience, developing at 40 ºC, I have got color in the pictures. The other steps of the process remained the same as Tetenal, Blix and stabilizer.
In the experiences after this event, I just added one of the components of the Tetenal developer, the one containing just a solution of CD-4, the color developing agent, to the Caffecol. And it worked. Then I tried only with CD4 and Sodium Carbonate and it clearly didn't work very well, giving a very thin and not defined image. Coffee was important, then.
I assumed from the beginning that a B&W developer is present in C-41 processes because there is silver in the emulsion and the dyes are developed with CD-4 but in the presence of oxidized B&W developer. The new developer I made with coffee differs from the Tetenal developer only in one component, the coffee instead of Hydroxylamine Sulfate.
Reading about this component, Hydroxylamine Sulfate, it is the Sulfuric Acid salt of Hydroxylamine, substance that can be used as B&W silver developer but explosive in pure state. So, the so called stabilizer, Hydroxilamine Sulfate is perhaps not only a stabilizer but also a silver developer. It seems that it can be replaced with coffee or maybe some other B&W developer too.
OK! With coffee it takes 30 minutes and with hydroxylamine only 3' 15". But we are still in the beginning.