I didn't see Aaron's comment before completing the battery replacement. Afterwards, the computer would not turn on despite multiple SMC reset procedures. Upon double-checking the comments I see the importance of pressing the gold button. I pressed the gold button before disconnecting the new battery, then pressed it again after reconnecting for good measure. Computer booted!

It would be good of iFixit to add this important step as most people probably don't open up every single comment on (seemingly) simple steps.

I'm an (unauthorized) Apple computer tech and have replaced over 24 displays on 21.5 and 27" iMacs. The only time I had a display fall off was when I tried using GooGone to remove the adhesive residue. It leaves a greasy residue that is hard to remove and will prevent proper adhesion of the replacement strips. My customer found that her 27" display had fallen off TWICE (both times it miraculously ended up on their office chair with no damage). I now use 91% IPA and the flat edge of a new spudger tool to remove residue. Never had a problem since.

I've used several different makes of strips purchased via amazon and they all work fine.