Sounds like a great trip, and your lenses certainly cover a huge range.

The 5dII and 24-105 are no brainers, as is the 50 for low light. But I wonder about the 100-400 on this kind of trip. There's almost no good answer because you know what the lens is capable of, and you're right that you'll miss it if you leave it behind. But bringing it will be tough too.

What is your system for carrying the 100-400 around mounted on the camera? That combo could wear you down after a full day (or days!) out and about without the proper solution. R-strap? Leave it in the backpack until you need it? I've hiked with my 7D/70-300L, which is a little smaller and lighter, all day with an R-strap, and it gets a little uncomfortable over time.

I guess what I am saying is this: if you choose to bring the 100-400, make sure you have a thorough plan for how to carry/use it.

A compromise lens would be the 70-300 USM consumer lens. You lose 100mm and some sharpness, but it's cheaper, smaller and lighter.

And check your insurance coverage! You're talking about bringing $5000-$7000 of gear all in, which is more than many people in SE Asia make all year.