No sound from earpiece speaker after screen replacement iPhone 5s

I got an iPhone 5s with a broken screen from a friend. The earpiece speaker was very quiet even at full volume, but it was usable in quiet environments. I bought a new screen to replace the broken one, and got one that includes the full speaker and camera assembly hoping that would fix the earpiece issue at the same time I replaced the broken screen.

Sadly, after the screen replacement I have no earpiece sound at all! I tried swapping the old quiet speaker back in with the new screen, and again had no luck, no sound at all.

Any thoughts on what the issue might be? I don't think I could have damaged a logic board, but I can't help but wonder if that's the issue. I am now missing one screw from the 4 screws listed in step 17 of the guide. The 1.3 mm didn't lock in so I left it out; these are the ones securing the front panel assembly cable bracket to the logic board.