Only five out of ten on a Do you know modern manners?.
Mind you, I was answering them in a vacuum. When going to a dinner party it's pretty normal to notify of dietary needs - and a good host should ask, anyway.
Bollocks to air kissing. To me there's three ways to greet people - proper kiss (cheek, not tongues, obviously...), handshake, or "Hello".
Of course it's okay to ask wedding guests for cash. One set of friends asked for cash donations towards two carefully chosen charities.
The cocaine at the dinner table. Hmm. Naivety - I have never ever seen cocaine in its recreational form, and the thought of my dinner party invitees taking it out in my home is laughable. Frankly, I wouldn't mind as such, but I am absolutely certain that the quality of conversation would deteriorate rapidly, and this ruin my dinner party...