I haven't read thro all the replies so I'm refering mainly to the O.P.
Jack, fantastically written and a very insightful and engaging read, which which I do agree.
I also think that differences in live performance could be partially due to the size of audience.
I believe Mika has said in interviews that he likes every member to feel part of the show, that it's being put on just for them. In a smaller audience the sutle flirting works well but I think that it loses it's effect somewhat when you upscale the number of people.
His more flamboyant performance while more masculine and perhaps seen as more acceptable also transfers better when you have an audience of several thousand people.
Either way I still find him extremely sexy and when I saw him live in May there were times when it felt like he was just sing to me (I'm sure all 2,500 people felt the same!).
I look forward to reading more of your Mika Essays!