For the front derailleur you'd need either a hydro Shimano shifter or the hacked guts of any eTube front shifter. SW-600 climbers shifters can only operate the rear mech.
Cosmetically poor 6770 shifters seem to go pretty cheaply, and if you're only using the Di2 electronics box in the shifters you don't need to hack hydro shifters - any will do.
For the front derailleur you'd need either a hydro Shimano shifter or the hacked guts of any eTube front shifter. SW-600 climbers shifters can only operate the rear mech.