1. I show Aces over a quantitative when my response is at the 5 level.0-4 (5♣), 1, 2 and 3 (5♠). I've heard people show 5/4 card suits at the 6 level (in case partner prefers to play in such a suit), but I don't think that would apply over such a sequence, though South might try 6♣ to try to show a really long suit. 2. 6♥ seems to play, and I guess 7♣ was a misunderstanding of 6♥. These bids (especially 7♣) are not good, but I think the problem started before) 3. North 60%, South 40%. South tried to show his hand naturally (though maybe 3♠ is not correct) and then North proposes NT with a void in South's main suit? I think 4♦ would have been a better bid then and there. However, after 6♥ why did South went on to 7♣, did he think 6♥ showed club support? Yeah, he's got 7 of them but he's missing the King and the Jack... I think 6NT would have been better then and there (in fact isn't this the contract North is inviting to with 4NT?)