As I said earlier, Loki speaks a funny mixture of Bislama and English.
But none of the others have done this.
Sophie was two and a half when we arrived and speaking English already. She picked up Bislama after a while and soon was speaking without an accent and never mixed up the languages.
Bethany was only six months old when we arrived. She spoke Bislama as her first language. Even though we always spoke to her in English, she would speak back in Bislama. It wasn't until after a lengthy visit to Australia that she began to speak English. Even when she was speaking English words, her sentences followed Bislama word order.
Matthew, who was born while we here (though not actually born here, if you know what I mean), learnt to speak in sentences. 'It's a ball'. 'Where's the car?'. He learnt both languages at the same time but always kept them distinct.
Loki, like Matthew was born during our stay here. He, as I said, speaks a mixture.
What would the experts make of all that?