Home Button, Charging Port, Speaker, and Headphone Jack Unresponsive

My iPhone 6s had a third-party screen replacement in August. After the screen was replaced, they did not put the two pentalobe screws back in the bottom. A couple months ago my home button became unresponsive. Today after my phone fell about two feet, my screen came off (attached still by flex cable so it still works). Now, my charging port, headphone jack, and bottom speaker no longer work.

The flex cables are not torn. From what I understand from other sources is that these cables need the appropriate pressure on them in order to properly respond. If I apply pressure on the bottom right portion of the main display (not glass), my headphone jack works. If I apply pressure to the bottom right corner of the glass, my home button and charging port work. I haven't been able to get the speaker to work at all though. The phone also no longer vibrates.

Do you believe this problem would be solved by putting in the two bottom pentalobe screws, or do you think there is more internal, not-obvious damage to the phone ? Would replacing the charging port/headphone flex cable fix the speaker and vibration problem?

Thank you in advance.