I personally think that Jing Jing’s accent is cool and I have just remembered one day in one of her old videos someone asked her why does she speak the way she speaks and she said that she gets it from her dad which we all know it’s bs her father speaks like a normal Australian man or someone that has lived there for the most part of life.I'm from the UK and there are many many accents. You're right that Josh is from Bristol but his accent sounds a lot more stronger/West Country the way the older generation would speak. Tbh I think he plays it up for what he would define as "comedic purposes" although he sounds very ridiculous and grating in my humble opinion. He even jokes about being part pirate from time to time (Bristol is where the stereotypical pirate accent came from with the weird 'r' sounds). I think a more accurate young Bristol accent would be if you watched a Maisie Williams interview. She was in Game of Thrones and she's from Bristol.
Both Jasmine and Josh have very strange accents to start of with and now they're both mixing into each other's accents + Bali influences. They both sound very odd. Not sure if other Australians can back it up but Jasmine's accent sounds very ambiguous/attempting to be exotic now whereas when she was starting out, she sounded very typically Australian. Her sister Jade has a normal accent so not sure whether Jasmine was more influenced by Jingjing or something.
It is true that Jasmine looks very much like her Polish father despite looking Eurasian but no her father doesn’t speak like her.