I'm not sure I can confirm that, no.
In fact, on further reflection I think the most important point is just that 'Wer von euch ...?' should not be translated too literally.
When you are asking a general question to a group, you should normally just use 'Who (here) ...?', and normally not 'Who of you / among you?' If you need a show of hands, you can also ask 'How many of you ...?'
Who wants to try the next sentence? Volunteers?
How many of you thought this section was confusing?
Who had a hard time with it? Come on, be honest, I need to know now, not after the test.
Who here / How many of you would be interested in an extra study session? Saturday morning? Sunday afternoon?
In English, I would still say we generally only use 'Which ...?' for a specific choice between A or B, or among A, B, and C, but not for an open-ended choice that could be any number.
The examples in #3 and #4 show that when we ask 'Which ...?', we often expect one specific person to be the answer.
The examples in #8 are indeed not incorrect, but they seem more formal to me -- as isabelll says, they have a teacherly, or I might even say pedantic tone. There may be some AE/BE difference on that point, or just a difference in style preference, but I myself would probably be more likely to say
Who's playing in the first team on Saturday?
Who here / How many of you voted CDU in the last election?
Who drank all my crate of beer?