Cool stuff !
First comment would be, on that run cycle it does feel a little stiff - both the anim, and the muscle sim. I think the lat has about the right frequency of motion. Looking at the back leg muscles, I'm not seeing the amount of follow through that I'd expect to see when the leg changes direction.
Fascia looks pretty decent! When 1.1 comes out (November) I think your fascia will get even better. We have some new features that will allow you shrink the fascia down onto the muscles and bones. You'll be able to get a lot more sliding in this pass.
Trying to understand why you're losing volume at the fat level with the coupled solve. Can you share some print screens / settings so I can get a better idea of what might be causing that issue?
Great progress though. Getting some nice action on the lats for sure, especially in that walk.