the XT rear der works fine with road brifters for Shimano... the front Der. will need to be swapped to a Road der...

The bigger concern is is The BRAKE pull ratios being different... what brake style is on the bike now??

Standard V-Brakes??? they will NOT work with road brifters... V-brakes are the Long Pull design, except for Mini-V-Brakes, and they can be found new or used. Tire clearance becomes an issue with Mini-v brakes, though... ...
Canti brakes? They DO work with road brifters...
Mechanical Disc brakes? They come in two versions... "Road" calipers have the Short Pull you will need.... MTB Long pull calipers do NOT work with Road Briffters.
How to tell if a Mech Disc Caliper is long or short pull? Measure the Actuator arm from the center of the pivot to the surface the cable clamps to... 25-ish mm(one inch) is Short Road pull... 35-ish mm (1 3/8 inch) is MTB Long pull. These dimensions are the same as the Pull of the LEVERS too.. measured from the lever's pivot to cable pivot point.centers.
There are no "standards" for hydraulic disc brake calipers, master cylinders, and how they interchange, Yet... that market is still in it's infancy.

good luck, and update us on how your conversion works out, ok?