You've got a pretty specific wish-list there. There's some problems, as mentioned though. To add to them though...

The number of cross bikes with disc brakes is quite low. The number of cross bikes with hydraulic brakes is ZERO. You have to use road discs if you're using drop bars, which means mechanical.

Combine that with your desire for an internal gear, and I believe you're out of luck. Something like the cross-check would have the horizontal dropouts you need, but lack the disc mounts.

Personally, I'd work through my priorities in order to arrive at a compromise.
- internal gears + disc brakes = mountain frame
- hydraulic brakes = flatbar
- dropbar = mechanical brakes or no discs