The ECL is a "gauge" (as is the EFB), so I'm not so sure you can add it to the EFB. Besides that, IF you add it to the EFB, it would probably be as an image (jpg/png) and not active (not able to be controlled using ALT+Arrows etc.) like it is as a gauge. Same applies to putting the EFB on the MFD. I think Captain Sim would have to program it into the gauges. :-/

Having a look at the gauges for the 777, the EFB is a combination of a DLL and a CAB file gauge (the CAB file has XML files that can be edited), but the MFD is a GAU file (Captain_Sim.x777.display.GAU) which can't be modified without hacking into it. So we can't modify them ourselves (at least not legally).