Thanks all, for your suggestions and comments, they have been most helpful.
Paulo - thank you for the link. The images reinforce the decision I made yesterday - based on your suggestion, to take the 11-24, specifically for wider perspectives where the Leica won't suffice.
Brown Bear, my assignment work is mostly architectural so I am used to schlepping a lot of gear on location, albeit with an assistant. That is why I am limiting what I take on this trip. Having shot in Iceland a few years back with limited gear, I know I want to go wider this time around and use the Leica S as much as possible. The widest Leica lens I have is the 30MM, which is why I am taking the Canon and 11-24 to supplement the Leica. As to the street shooting, the Canon with the 28, 40 (or 50 1.

& 85 will fit my needs nicely. That particular combo is fairly light on my shoulder in a messenger bag.
Nancy P, I haven't tried astro photography yet. One of my favorite adages: "if I knew I was going to live this long, I would have taken better care of myself." I do a bit of weight training, I do trails slowly, what's the rush? and watch for surface issues as I hike.
Tony, I had an M9 once, I just couldn't well relate to a RF. I did use a couple of the images I shot with it in my book however. I can't imagine shooting with one small prime. While I like the 40/50 perspective for most of it, but I do find myself using the 28 and 85 as well. I take your point about shooting what is in the range of capture however, which is why I don't like using zooms. I find myself hunting for a shot when I use a zoom instead of discovering it as I do when I use a prime - and zoom with my feet.
So gang, this is what I have (98%) decided to take. Leica S with 30,70 (still undecided about the 120). Canon 5D IV with 11-24, 28, 50 1.8 and 85 1.8. All of this fits in a small roller case for transport. I fill my shoulder bags with clothes and toss them in my suitcase until I get to the hotel.