On reassembly, fix the earphone speaker before the top sensor assembly. The first step is to glue the Power and Sensor Cable down on the iPhone base. Then put the earphone speaker on top of the cable, oriented as in the photos. Then bend the cable over the speaker and reassemble the top sensor assembly.
The right hand screw thread stripped on my repair. I reassembled it with only the left hand screw holding it in and it is working OK.
I could not reassemble the retainer. The legs would not go back to where they were meant to go and I badly bent one in the process. I replaced the retainer with a small dop of Blu-Tack ("a reusable putty-like pressure-sensitive adhesive"). This gets squashed down when you replace the logic board. This keeps the camera correctly positioned and works OK so far.
During reassembly, note that this small 1.5 mm screw goes into a thread in the head of the larger 4.8 mm standoff screw near the headphone jack.