The three 1.3 mm screws are very difficult to distinguish from the 1.5 mm screw. I spent a long time with a magnifying glass trying to tell them apart. For the other steps of the repair, I kept the screws in a tray compartment along with the piece that they connected, but for this step I recommend keeping each of the different types of screws separate.
I noticed something very strange when reattaching the cable. I tightened both of the screws in Step 25, and tried pressing the power button. It did not move. Then I slightly loosened the right screw in the picture (the one toward the center of the phone) and got a satisfying click when I pressed the power button. My initial tightening of the screw was snug, but not overly so - about the same torque as was required to release most of the other screws. So many people have problems with this button that there might be some sort of design flaw in the power button assembly, which partially manifests itself by very small tolerance on the tightness of this screw.
For me, aligning the connector when putting things back together was the most difficult part of this repair. Unlike reattachment of the radio antenna in step 11, it is very difficult to see whether the male/female are aligned properly before applying pressure. Unfortunately, I have no secret as to how to accomplish this, other than to say that my WiFi is working after the repair.
I tried this at first with a plastic pry tool, and the adhesive was so strong that I broke the tool. I then used a large screwdriver and applied pressure very slowly along various places on the outer side of the battery. That eventually did the trick.