I've taken some final measurements but they don't look promising, my conclusion is that the wii software mod was messed up form the start, or (most probable) the PMS is fried or defective.
Wiis can just randomly die during trimming sometimes. We have no idea why, the surgery just fails. Getting a replacement Wii would be the simplest option
You can scratch the soldermask off the trace that feeds the pad and solder to that spot. Also do you have a second cell on hand to wire up? Sometimes Wiis won't boot with only one cell connected
I've been trying with two cells, before I make a rash decision I might harvest a bms from a random lithium ion cell in a old phone first to see if it's just the battery's being low. Btw I really appreciate the help.