Pallinens get their skin color because their blood is actually blue. Their arms, legs and sometimes tails are all a darker shade of purple because in those areas it is a lot more pigmented. If you were to skin a pallinen (not recommended, they are a lot stronger than humans and if threatened they will rip you in half. Also, murder is illegal,, so uh, yeah) you would see that their lighter colored skin is somewhat transparent and their darker skin is fully opaque.
Pallinens have yellow teeth, because all their bones are yellow, and blue tongues because blood blue.
Pallinens as mentioned above, are insanely strong, and could definitely bench press a whole ass whale, though they wouldn't, because pallinens are very passive creatures and know that would hurt the whale.
Despite being passive to most creatures, they are somewhat aggressive towards humans, mainly being because humans have a history of treating pallinens not so well.
Note: They never get physically aggressive with humans.
Pallinens are very family oriented, a family often stays together for generations. Because of this pallinens often have pretty bad separation issues, as they didn't evolve to be separated.
Info about Vincent:
Vincent is only half pallinen, the other half being human. So yes, this does mean it's possible for a human and a pallinen to reproduce, though it's very difficult to make happen, and only born female pallinens can reproduce with humans.
(All of this only applies to natural birth, the Baby Machine can be used for any combination of any creature able to consent that Shinnal was aware of at the time of making it. So basically just humans, pallinens and extentions of the two)
Pallinens aren't actually affected by pot at all, Vincent was just lucky to be able to enjoy the feel goodness AND be able to work probably.
Vincent was actually born with four arms, though his lower arm bones weren't attached to the rest of his skeleton, so they had to be amputated because they were going to just be a inconvenience. He does still have the scars, but they're very small now since the surgery happened when he was a baby.
Vinny is stronger than most humans, though not nearly as strong as other pallinens.