Gabriel,
Are you actually going to be away from electricity for a solid week, or will there be a chance to recharge batteries.
I have to say, these days I would not want to shoot film on a rare occasion like the one you describe. It's a lot of getting film through one airport after another and then having a lot to develop at the very end, both of which are much bigger problems than they once were. So, on trips like this I leave my film equipment behind. Last exception for me was when I was in southern Africa in 2006, but that finished it for me. The Heathrow terrorist incident that year meant that suddenly, for my return flight home, the airlines were not going to let me carry my dozens of rolls of undeveloped film on board with me--at all!
Fortunately I not only got the word on time but was able to find a service in Cape Town that would do overnight E6 development for me. I ran into some other poor guy who was in the same boat except that he had a couple of dozen sheets of undeveloped 8x10 sheet film representing his work in South Africa that trip. When I left him, he was still wondering what to do.
Yes, that was a stroke of really bad luck, but I think it represents what we all know: the film shooting we love is becoming more taxing even if you are just walking around your own town and developing a roll or two. The problems get a lot bigger when you travel internationally.
So I would definitely take the M8, the GF1 as a backup, and lots of batteries. Too bad... if not for that I'd try to shoot the whole thing on my favorite, Portra 160, or on some other film that would keep the contrast under control.
Tom