Shimano hydraulic brake swap/installation-type question...

[kohlboto]

Okay, so, I'm going to be switching my Parlee Chebacco from Mechanical/Hydraulic to di2/Hydraulic. The internal di2 wiring looks pretty straight forward and I think the brakes shouldn't be a problem. But, I'm wondering...can I can keep all the brake housing on the frame (and connected to the calipers) and simply swap out the levers? It looks like I just have to uncouple the housing from the mechanical shifters and swap them over to the di2 shifters. Am I correct in this assumption?
Obviously, I'd have to deal with the mineral oil and bleed the brakes again but it seems suspiciously straightforward to me.
Anything else I should take into consideration before attempting this?