While I applaud their persistence, that reads like a list of stuff that could have been done on the mainland with help from the ROV supplier, before leaving for the big trip.
A. Neither John Clauss nor Walt Holm ever saw the ROV until it arrived in Fiji. The ROV belonged to, and was the responsibility of, the contractor who is based in Texas.
B. I don't know what checks were carried out prior to shipment but the contractor believed the ROV to be in good working condition at the time it was shipped.
C. If you know how to fix something before it breaks please let me now.
D. The principal problem was the lack of a second back-up ROV. That lack was due to a lack of adequate funding to pay for shipping a second ROV. We tried our damndest to raise the money to fully fund the expedition. Many on this Forum contributed (Thank You!) . I'm not much inclined to listen to Monday morning quarterbacking from those who didn't.