Not necessarily. They’re wired in a matrix so there could be a break at any point between the key and the ribbon connector and this might not be anywhere near the key, although more often after a spill it will just be corrosion on the contact pads. If it’s just corroded this can sometimes be fixed by polishing the pads with a fibreglass pencil.
Make sure you’re using a Philips driver and not pozi, they have different taper angles and are technically incompatible
Alcohol will often contain at least a small amount of water, which will promote corrosion of the contacts. Anhydrous alcohol would not have this problem however as it dissolves adhesives they may propagate to the contacts and coat them sufficiently to cause issues. Using heat will soften the adhesive while keeping it in situ. Plastics will also soften somewhat so care is required.
In all likelihood the different error codes mean something like:
•Cell not reaching it’s fully charged state within the prescribed time (symptom of old cells)
•Cell is overly-discharged (If it was drained to preserve the backup caches and not recharged immediately)
•Cell is too hot/cold
•Cell did not meet the prescribed capacity requirements upon conditioning (symptom of old cells)
Since they're only spot welds, drilling them out doesn't require going very deep into the body. No more than a millimetre in fact. So the body will be damaged, but only on the inside of the unit where it won't be visible after reassembly.
Hope that helps!
It took me about 48 hours allowing two coats of conductive paint to fully dry; maybe two hours actually working on it, figuring everything out as I went along.