My veterinarian is implanting a microchip tomorrow. He informed me that all microchips are universal now and that there's not a "European" microchip. Is this accurate?

As long as it's a 15-digit code it should meet the international standards. The USDA site has this info.

My dog already has a 10 digit microchip. Do I need to get the 15 digit one?

A: You can rent a scanner to take with you on your trip or re-chip your dog to the international 15 digit ISO standard. Per the USDA website:

A rabies vaccination must occur AFTER microchip implantation. The rabies vaccination may be administered the same day as the microchip implantation but any rabies vaccination before a microchip is implanted is invalid. If your pet had a non-ISO compatible chip implanted at the same time as or before your pet’s most recent vaccination, your pet will not have to be re-vaccinated even if it had to be re-microchipped with an ISO compliant chip to travel to the European Union (EU). Remember, the number and implantation dates of both microchips must be documented on the EU Health Certificate and at least one of these microchips must have been implanted before your pet’s most recent rabies vaccine.

Is the rabies vaccination absolutely required before importing a dog into each country, or will the vaccination titer test suffice?

USDA and international quaratine offices require that the rabies shot must be current. for UK, It must be done at least 3 weeks before entering the country, but after microchipping. The rabies titer test does not qualify. For Japan you must follow the required quaratine process, they will not make exceptions.

Should I bathe my dog pre-surgery?

The doctors feel it’s not necessary to place your dog under such stress before such an intervention. You can however use dog friendly wipes before and after surgery to clean your dog avoiding surgical areas as they heal.

When should I stop giving my dog medication leading up to surgery?

At your vets and each surgery centers descression, All normal medications should be given until the evening or morning of surgery. After surgery, the doctors will recommend how to proceed depending on the needs of your dog. Again your doctors will clearly explain what you should do prior to your surgery day.

Do you get any updates during or immediately after surgery?

The doctors will update you frequently. They will provide you updates in person if you choose to wait at the clinic during surgery or via telephone if your services are working.

Unless your dog is small enough to fit comfortably in a small carrier bag, a stroller is recommended for transporting it in the airport (provides an enclosure that some security may ask about) and is necessary post-surgery to take your dog to/from places with you when activity is significantly restricted.

A stroller made for a child is not ideal, there are specific strollers made for pets, with a flat bed, and with the enclosure so that they cannot jump out. A sturdier stroller is recommended so that your dog has a smooth ride especially over difficult terrain such as cobblestones and grass/dirt. Some also have, for separate purchase, a weather cover in case it rains. It is better to use a smaller stroller when navigating the trains in Japan with your dog.