Back in the 2013 the Shimano Alfine series would be your best bet if you wanted Hydraulic Disc Brakes and Di2. They feature high braking power ideal for cyclocross and on-road riding, ergonomic hood and lever design and the reservoir tank provides pad clearance auto-adjust to maintain consistent pad clearance.
You can adjust both the lever reach and free stroke.
These are compatible with the SM-RT99 centerlock 140mm and 160mm rotors and WH-RX31 wheelset (which as no standard rim brake track.) These require the BR-785 dual piston hydraulic disc calipers. They do not have the special wiring port required for the SW-R610 Sprint Shifters and a SM-EW90-B 5-port junction A is required to use the SW-R600 climbing shifter.
Each shifter has one e-Tube port and a pair of shifters weighs about 500g.