Your "likely choice" seems pretty darn good. Your longest lens will 560 f/5.6. Unless you have a second 1.4x TC to stack on the 200-400 f/4 + 1.4x. Your wife will max out at the equivalent to 480 f/4 without a 1.4x TC.

You mention monopods but no tripod. I understand if you'd only be shooting wildlife, but I would think that a tripod could be very helpful with landscapes.

Sounds like a great trip.