The glossy look the Cenobites now have may look a little goofy. However, they also add more light to the design, which makes the description, "Demons to some. Angels to others," all the more fitting.
Another quote, "We have such sights to show you," is given added meaning by the end where Voight is exposed to Leviathan's insides and becomes a Cenobite himself. Of course that saying would be saved for such an occasion, it's the Cenobites chance to give their victims a glimpse at their god.
The original Cenobites were inspired by the Fetish community of the 1980s, with a focus on leather and bondage gear. The new designs are more in line with extreme body modification sub-cultures, such as Modern Primitive, focusing on cosmetic alterations and decorative piercings.
Trevor originally met Riley through a 12-step programme, and it's later revealed that he was working for Voight the whole time to find victims for the puzzle box. Recovering addicts would be ideal targets, as their disappearance without a trace could very easily be blamed on them relapsing; always assuming someone was looking for them at all and that they hadn't already pushed everyone away.
The Cenobites have a warped sense of reward, such that their gifts would be punishments to the sufferer. This works in reverse— Riley opting not to accept a reward leaves her with nothing in the end, the safest option for her survival and well-being, and technically the "best"—and this is the only option we see the Cenobites genuinely consider a punishing choice—they see it as accepting a life of pain and torment knowing the hurt was caused for nothing. They're not wrong, but Lament is still Riley's triumph and moral victory, so this is the only option the Cenobites have pity or disdain for.
The puzzle box is the perfect gift for a remorseless serial killer. One could select enough victims to complete all the configurations and summon the leviathan. The victims would disappear, leaving the killer to avoid any punishment. Finally, they could get away scot-free if they selected the Lament reward, or they could choose the Leviathan reward and become a Cenobite themselves.
While Colin is running from the Cenobites, he encounters a pregnant Cenobite. Just what the hell happened to that person that resulted in them becoming pregnant? Or, if you want to delve into Squick territory, was the baby there before or after the Cenobite transformation?
If Riley did indeed choose to resurrect Matt, he would likely be completely skinless, which aside from being horrifying to look at, would also mean he would be more vulnerable to pathogens; or otherwise he'd likely perish immediately from the traumatic shock and agony of having no skin. He would die again, and Riley would have had to see it for herself.
