I'm not sure on Kate's dress tonight. I like that it isn't pale blue and I like it's a little different but I think maybe it would have been better not in black it is a bit matronly, it's nice to see her in the floaty gown look though! Also like I said earlier good to see the sparkle, I think we can all agree she must be lurking on the threads 
Camilla has the best outfit by far for me. But I'm a big fan of the queens tiara I think it might be one of my favs Especially with the emeralds!
Kate's necklace is this one 'the Nizam of Hyderabad necklace' which was a wedding present to the queen (according to Twitter) Kate has worn it before curly so you may well be right! Good spot.
Ps I take back my earlier moan about lack of photos Kate sorry 