I am not at the computer in the printer room right now but in Cura there is a Printer Settings (or some such) plugin that you can add. With it you can set something like shared heater. Also in multi-extruder cases make sure that the extruder idle temp is the extrusion temp. And I use a gcode find&replace macro to remove M104 T[0-7] S0 but I think that may have been fixed in the current revisions of Cura.
In general I also filter out the Tn Gcodes and use the slicer to insert calls to TOOL_START=Tn and TOOL_END=Tn and use those macros to switch extruders and stuff. Makes it more controllable in Cura, IMHO anyway 