Those little screwdrivers are easy to mix up, for those of us without ultra-perfect vision! Once I used the correct screwdriver, and my 13yo son's little fingers and perfect eyes, it went smoothly! Also my son noticed that the rubber piece around the camera len was covering the camera; it likely slid out of place when sliding off the back cover. A little playing around (with plastic tools only!) and it looks perfect now!
I'm over 40, I wish I read your tips first! both a magnifier and tweezers would have helped, and possiby prevented the spark... It's charging, fingers crossed that the tiny spark wasn't enough to fry anything!