"-Can i sell my html game made with C2 on platforms such as MARKETJs? they want a source code nope? How will they get it if it's made with an engine? "
At the end you get a valid html5 and javascript file, as well as ressources, so that shouldn't matter
"-Can i sell my ios/android game made with construct and wrapped with cocoonjs? Here i'm sure companies want source code. So i can't?"
Don't know, but I'm sure not all ask for source code
"-Ad mob, mopub, leadbolt and all the advert stuff give SDK. I can't use it neither if the game is developed with C2?"
You would have to adapt their SDK (through a plugin or execute javascript action)
"-Why there is no ads companies for html games but so lot for mobile games?"
can't anwser that