There are cable lever to hydraulic disc conversion units this year.. not cheap.
but they are able to be used with road levers..
TRP http://www.cyclocrossworld.com/trp-p...c-brake-system

Hope http://www.cyclocrossworld.com/hope-...ic-disc-brakes

Trekking bars Will use MTB hydraulic brakes ... as is..
I have Magura HS33 on one bike, they are the hydraulic rim brake..
They discontinued the HS77 road master cylinder/lever decade+ ago.

taking off the hydraulic disc caliper + lever, and going with Avid BB7 road disc mechanical brakes
may be simpler
and the cheaper method to gain road bars and disc brakes.