Can I remove FRP with Heimdall/Odin? I have a Samsung Galaxy S7 with FRP-locked, USB Debug is off and I am trying to disable FRP and enable USB Debug. Is there any way to do this with Odin or Heimdall? 

I also have the stock ROMs for the phone, and no, the previous owner does not remember the gmail account she used for the phone. The Model number is G930P, and the carrier is Boost Mobile (Sprint, USA).
The answer to your question is no.

Without a Samsung Engineering firmware load that has adb and USB debugging enabled in the setup wizard this is not possible, and I have never seen one leaked out for any Snapdragon based S7, so the answer is simply no.

Remember, FRP is DESIGNED not to be able to be bypassed or defeated, every time a exploit comes out, it get's patched, and this device just got another security update this month.