Regarding lenses, I would look at upgrading your 70-200 to a 2.8 II if you need that focal length for low light situations.
I have that lens - be careful it's a hefty one to carry round weight-wise, especially with a TC attached.
Looks like a nice sensible collection, just leave at home what you dont need...
Yep, and replace the 5Dc with a crop; it's *very* nice to have a digital 1.6 TC with improved AF, like having a complete range of extra lenses
I've a rule to limit the amount of kit I carry. The limit is what I can put in one bag (LowePro Mini Trekker AW) and what doesn't fit in there must stay at home. Very occasionally I also take a monopod or a tripod but I find those a nuisance, really.
I find that selecting my kit before a shoot helps me focus and produce better pictures. A good preparation is important, not only to save weight .