Thank you all for the comments. As it seems K-1 is still not on stock in my country, I will have to do with the K5IIs and lenses that I have now: DA 15, FA 43, FA 77 and the Sigma 35mm Art. I also have the kit lens (which is WR as far as I remember).
I am tempted to take the camera with DA15 and FA43. Sigma is big and heavy, and I don't really know if I should take the 77 or not. I mostly shoot landscapes and I don't wanna change primes too often in a hot and wet environment... on the other hand my girlfriend is coming and maybe some portraits with the 77?
Except for the Sigma, I have space for 2 lenses in my small camera bag. I have a bigger one but I don't want to take that one.
Also, still not sure what to do about underwater photography. I am tempted by the Olympus TG-4 as it seems better then Ricoh WG-5.