I think the pic of Ozzy is from a yet unseen episode. In the ep 2 challenge they had to go back to the beach before the next person could go and this does not match the pic shown.

It looks like Eliza in the water to me although it is hard to tell. The platform is purple and it's team challenge not individual so pre-merge I'm guessing.

The Jonathan pic without the face paint I think is from a seperate challenge than the one we will see in ep 3. In the pre-challege ep 3 pics you can see Jonathan's face paint and I don't think it all washed off that fast.