Hey there. Good first pass and nice to see you posting regularly.
Some comments/ questions:
With the fascia, are you using Ziva cloth? To me it looks like the shapes are 'baked in'. By that I mean the valleys between the muscles aren't coming and going as I would expect. This can happen if you run the fascia as tissue rather than cloth, if the tets are too big.
How did you model the fascia? Until the newest cloth features are available to trial users I would recommend using a shrink wrap + deltamush, or ncloth negative pressure to get a nice even distribution for your base model. Once you have that, copy the mesh, and use that as your base model for a Ziva cloth fascia.
Behind the tricep, it feels like the fascia is being pinned to the ribcage and not following the muscles when the front leg reaches forward.
You can see the fascia solve is suffering a little from popping muscles from the muscle solve. The good news is, you can revisit the muscles, make that pass better, and plug your results directly into your fascia scene.
Also doing another pass on the animation to remove the popping etc will help carry your muscle -> fascia -> fat sims.
Keep it up!