so an Ultegra 2x10 setup, with 53-39 front and 11-28 rear (wow, thats an insanely high top gear)

what kind of flat-bar shifters can you work with your missing fingers? flatbar trigger shifters generally require an index finger AND thumb on both hands.

thats a really nice 'race' bike, seems a shame to chop it up like this. if its a 2012 like your ink, it must be nearly brand new?

I'm not sure I understand the mountain bike + speed part. a hybrid is not that different than a cheaper light duty hard tail mountain bike, with street tires. putting smaller slick/semislick tires on your mountain bike will get you more than halfway there, unless its a full suspension downhill bike or something.