It should work. MEID should be attached to the logic board. Most likely the grounding clip came loose (near headphone jack). You might also try restoring the phone and at the setup screen connecting to Itunes. I haven't had Verizon since the iPhone 4 but I remember sometimes I got "No Service" after restoring and couldn't activate the device.
Replacing the iPhone 6 touchid sensor/home button is a very risky move. 99% of the time you will be unable to restore the phone and may encounter other issues. I am thinking this is the issue. If the original home button and touchid flex cable worked, you should NOT have replaced the home button. It may work if you put the original cable and home button back.