3) Used brifters, Tiagra, 105 or equivalent. Not sure the going prices, but it should be about $100 or less.

Dream on, have you looked at scambay recently. 105 9 speed stuff is going for more than the 10 speed.

I have done this with 2 bikes, it is fun and the minimum cost is about $450 unless you are getting some free stuff. Good luck.