Yeah, I've had a love-hate relationship with muscles in Daz (the software I use to create the images). Folks may remember a scene with Santino when he was bulging out of a badly fitted suit. I have since learned how to fix that issue, but it kept me from going really heavy with the muscles. And, adding a lot of vascularity to a body is another layer of complication. Since I started, there is an asset I could buy and use to add more vascularity to models, but it would change how they appear. Once BBN is finished, I will debate whether to do a remaster and, if so, I'll make some of those tweaks.
Body hair is a long-standing issue with Daz and the subject of many threads over on Discord and among VN creators. I have since found a body hair resource I like, but it wasn't available when I started. That said, there is an in-character reason Ronan is fully shaved and that will be shared eventually. For some of the other characters, it was simply an asset issue.
Cheers!