Hello, Raymott.
I realise you used both forms of the verb have in your examples. Can I take it as a kind of implication that you think it doesn't matter whether people think of Who of you as referring to one person or more. Or, you meant to show these two forms are both acceptable, in right contexts.
'Who' can be either singular or plural. If you ask some people, "Who [of you] watched 'the Simpsons' last night?" the answer might be no one, one person, several people, or all of them.
The verb isn't important here because in the simple past tense, it's the same for singular and plural.
Suppose some one tried to escape from a gaol, he returned to his cell without being noticed after he'd realised he simply couldn't do so. The alarm was triggered anyhow. The guards examined the place where the prisoner tried to escape and there's clearly evidence that only one person was there when the alarm went off. All the prisoners were called to the hall and a captain was ready to deliver a speech.
In this context, if the captain wants the prisoner to turn himself in and have already anouced that one prisoner tried to escape, I guess he is not likely to say Who of you have tried to escape, instead of Who of you has tried to escape. Because he is clearly reffering to one person.
Am I right i thinking so?
Yes, if he knows that only one person escaped, he'd use 'has'. In the present perfect, the auxiliary is different - has, have.
Similarly, if I wanted to talk to the leader of a group of people, I wouldn't ask, "Who of you are the leader?" But I might ask, "Who of you are willing to talk to me?"
"Who of you" is not common though.
Many thanks
Richard