3 days from Hawaii to Sweden, door to door? I am pretty sure many mainland USA customers rarely receive their goods from Hawaii this fast, so this is truly astonishing. Unless you mean New York to Sweden, in which case it's more realistic, but in no way 100% guaranteed.
In any case such a courier service would cost a fortune. That's the main problem with shipping frozen kava. It's 80% water, so you basically pay to ship water around the world. Plus you need to pack it in insulated containers, perhaps with an ice pack etc.
Trust me, we ship kava around the world, and customs officials are often suspicious and hold packages for days or weeks. A package with some frozen raw plant material would most certainly attract a lot more attention than dry kava.
There's no way sourcing frozen kava from Vanuatu on a weekly basis could be economically viable for any kava bar. We are based in NZ. Vanuatu is a 2 hour flight away. And it still wouldn't make sense. For a start, you've got constant delays and flight cancellations (especially now), second, the cost of airfreight is astronimical right now, likely far in excess of the actual per kg cost of kava.