Two thoughts. One - the easiest way to reduce weight is to limit your carrying capacity. Four Ortliebs, two of them big plus two racks and a good sized front bag is a lot. I'd pass on that front bag and use 4 of your front Ortliebs. (You get to save weight on that front rack also. Keep the LowRider.) Other thought - clothes. The perfect packing job has you wearing everything you brought on the worst weather day of the trip and it is enough. Granted, that can be a tough target but lightweight warm hats and some other lightweight specialty items can go a long ways if the weather turns worse than planned.
When I crossed Wisconsin 50 years ago in October with a very light sleeping bag, I had everything on the second night. Slept well. Woke up scared because I knew I was close to the edge warmth-wise and saw zero frost when I woke up. ("This could be bad" thinking of the upcoming nights.) Found my WB frozen. "So it was actually cold. Whew!" (Forgot you don't see frost among the pines I chose for my campsite.)
That Wisconsin trip, my bike probably weighed less than 50 pounds loaded minus WBs. 24 pound bike with sewups. No tent, A tarp and line for rain. Not the approach for us older folk but it worked. Slept under the stars 6 nights, motel one. Tarp got used once or twice,