[Jnat]

1) Dealers do this work all the time, human error can always happen but is not likely and normally easily remedied.
2) My bigger concern would be the rodent, you MUST change if possible where you are parking your vehicle to change the habit of the rodent. Moth balls placed under the hoods has worked from what i've seen in the past, if it's in a personal garage, set traps.

My perspective comes from almost thirty years of Service Manager (dealer) and now Fixed Ops Director (dealer). I've probably seen 1k engines replaced and any issue caused by a technician was easily resolved. I've seen far less rodent damage but probably seen it over 150 times. The rodent should be your concern, good luck.