Can a potential Supervisor leave a hint on you in the scholarships and influence somehow the selection?
I would expect that absent firm rules that professors lobby pretty hard for the students they most want. It isn't a question of leaving some subtle hint. 

There might be rules against it, of course, and that might dampen it down a bit, but ....

There might even be "horse trading" among senior professors. 

But it is just another form of competition. Having a professor strongly advocate for you doesn't guarantee much if other professors are lobbying for others and the money is limited.