You have some great questions. I’ll do my best here.
I can’t comment on Hawaii, because they are part of the United States. I’ve never had a client travel there. However, I do know that immunizations absolutely must be up-to-date. Also, not every state requires a dog license, however, everybody must have a rabies shot. Proof of that can be gotten from the veterinarian.
I am not sure if the cruise line actually requires the medical records however it would be silly not to ask for a rabies certificate at the very least.
If the animal has fleas, that would need to be addressed immediately. Responsible service dog owners keep their dogs impeccably clean.
Biting is a different issue. I would hope that the dog has been trained not to do such a thing. However, accidents can and do happen. If the trainer is recognized the DOJ, if the dog were to bite someone the DOJ will cover that as far as a lawsuit for injury being filed against the handler. Of course, things are different outside of the USA.
Taking a service animal on a cruise That visits multiple countries can be a regular pain in the rear end. Handlers need to get in touch with each Embassy for each country and ask for approval to bring their animal into the country.
I hope this helps!
Happy cruising!
Edit….sorry, the ADA is a law, not a government agency.