Just to update: all went off smoothly enough. Bit slow through the border at Narita lead to less time than we’d have liked to pick up Shinkansen tickets - complicated by JTB tickets only being issued by machines outside the gates. Once we got pointed in the right direction we were fine and no issues at Ghibli Park at all. The first two areas are fairly minimal and not many visitors were doing those (I presume they are keeping the numbers very low). The warehouse is much bigger and busier.