It seems you are all over the place. Your target is full plate = 6.5 x 8.5 inches, but you consider anything from 6x9 cm(!) [~2.3 x 3.3 inches] to 5x7 inches, but have ruled out the only solution that could actually accommodate full plate, i.e., 8x10 inches (unless you want to get a custom format frame and custom bellows).
The second question is, why monorail? If you want to use small lenses, this usually also entails small coverage = little movements. So why not a field camera; certainly lighter.
It is pretty straight forward that larger format = more weight. In terms of how rigid you want your system, it may depend a bit on your style. I am quite happy with the classic level. Metric will weight a bit more, and you will gain a couple of geared movements, but certainly a viable outdoor option. Monolith series for outdoors seems a bit overkill. Discovery may save a few ounces, but not sure whether it is worth it.
I do carry an AS 4x5 classic compact outfit with 141 mm frames and quite a bit of add-ons, weighing about 50 pounds without water. You may get it down to 40 pounds, maybe 35 if you go bare bones (3 small lenses, no filters, no extension rails, no tripod head, ...). If you are fixated about the AS as a camera, but have trepidations about the weight, this is a good reason to get into better physical shape. I started hitting the gym and the pool to get more out of my camera hikes.
I think a major advantage of the AS is the modularity. See what you like, modify it if you don't. Let the system grow with your own development. I started with a compact version, but now also have a telescopic rail for longer lenses. I did not go for orbix, and after using it for a few years, do just fine with base tilt. But have been toying with getting the 8x10 conversion kit. Although I also did quite a bit of freeting about the "perfect" set-up when I purchased my starter kit, rest assured, it WILL change. I think the AS is a wonderful system. It was=is my first LF camera, and although most people will say that one will switch cameras particularly early on, I have not seen any need to do that. I have upgraded lenses (e.g., SA 90 to XL), but not the camera.
In terms of models, I visualize the AS system as follows:
first, decide on which format (4x5, 5x7, 8x10 ...)
Then think about how rigid you want your system (Discovery, classic, metric, monolith)
Then think about the rail support: compact (= folding), straight rail, or telescopic rail and how long, which needs to be according to focal lengths and magnification.
Then think about potential optional accessories: orbix, different bellows, viewfinder, shade system. Misura and some of the newer models are outside of this type of consideration.
Once you dissected the various components, then the number of available options becomes much more manageable. Also remember, whatever you decide, you CAN change it later.