Took me a little over 4 hours, but seems successful. Most of the middle row on my keyboard had stopped working, I was having to use an external. The new case works fine. The hardest part was definitely the logic board removal, but just be patient and methodical and use the spudger to loosen the adhesive that binds the microphone to the upper case. I also encountered two screws that stripped when unscrewing, and had to use some creativity to release those parts. 48 hours after replacement, everything is working, and the new keyboard is definitely an improvement. Time-consuming and stressful but so much cheaper than authorized repair.
One of the screws started stripping and was on too tight to come off. I noticed I did not need to transfer this part to my new case, so I went ahead and used a dab of lubricant, then gripped the rim of the screw laterally with the needlenoses. It came loose, and I was able to reuse it.
The 2.5 mm screw was on too tight from the factory or a previous repair, and would not come off. I had to heat a blade and slice around it. All the other screws came loose, so the subwoofer assembly came loose after slicing around the 2.5 mm. Then I was able to grip it with needlenoses and remove it. The 3.2 mm screws hold it down adequately so I did not replace the screw.
These screw holders were broken when I opened it up, it seems a common problem. I used a very tiny dab of strong glue to put the holding rings back onto the battery. When I replaced the battery they were held in place more by the push of the screws than by the glue, so I have no worries about them coming loose. Their main purpose is just to get the spacing correct from what I can see.
This part was highly stressful. The microphone/left speaker assembly are fused to the underside of the logic board. As you are facing the project according to the layout in these photos, the mike assembly is on the right side of the logic board, towards the top end. It is fused to the logic board but it also has adhesive sticking it to the upper case. As you lift, you have to insert a long spudger flat end down into that corner and move it back and forth between the mike assembly and the upper case, and it will release. Be very patient, focused, and slow. The spare part I bought from iFixIt had an extra speaker there in case I messed up, but I did not need it.