Hang on, the SM-J737a isn't an S7, it's a J7! That's a completely different phone, so swapping motherboards isn't an option: it's unlikely to even fit physically, and peripherals like the display are completely different. So the G930's motherboard won't be able to drive the J737's peripherals: the connectors are unlikely to be compatible or in the right place, and even if they are physically compatible the drivers will be wrong. If you want to use the G930 you need to get the screen fixed.
The good news is that the IMEI doesn't matter: put your SIM in a different phone and the number moves with it. In fact while I don't know US law on this, where I am in the UK it's illegal to modify an IMEI, and I'd regard anyone who offered that "service" as shady at best (since the primary reason for doing this is to work around blacklisting of stolen phones).