just be cautious if your having any sort of knee pain - riding fixed can damage your knees if you're not carefull or if your are recovering from an injury. I would highly recommend brakes, as the back peadaling to slow/stop yourself, while excellent for strengthening muscles, is a common source for causing issues. Also, DO NOT run too big of a gear. Start small, then work up to bigger gears. As far as brake lever type and placement, maybe go with a cross lever set up since you are running a drop bar. Are you reusing the mavic elite rims on the eno hubs? Sounds like a sweet project, just make sure it doesn't float away it'll be so light...