Home button not working after replacing screen

Hello all. Forgive me if this has been answered before, but I couldn't find the exact scenario when searching your forum. I replaced my iPhone 6 screen (just the LCD/glass/digitizer and transferred everything else). The screen worked great, but I found my home button wasn't working. I then switched the button out with the button from another iPhone 6 I also need to fix (different issue). That button didn't work either

I thought I had narrowed it down to the new screen being the issue once I swapped buttons. I then put the original screen and button back on the phone just so I wouldn't lose the parts while I ordered another replacement screen. I was expecting the home button to work with the old screen now in place, but it still doesn't work.

I now need help figuring out where the issue is. I've only replaced a screen a couple times, so I'm no expert, but I'm thinking there's something wrong with the back plate that I had transferred to the new screen. Maybe one of the cables is busted?

I guess my big question is, if I buy a replacement back plate, which I saw isn't very expensive...will Touch ID work with that aftermarket back plate? If not, I'd like to then continue troubleshooting with the original back plate and figure out if I can fix the problem?

Suggestions? Answers? Thanks in advance!