I'm a total newb to disc brakes and am trying to decide between a Soma Wolverine and DCD. I have a good deal potentially on an older 2015 Ultegra Hydraulic group and just want to make sure it will fit on these bikes.

Shifters are ST-RS685 2x11sp. Brakes are Shimano BR-RS785.

I suppose I should try mechanical first but the deal here is pretty hard to pass up.