They should be considered as furries, no skin seen, all of their skins covered with fur. We don't have furries, so Vastayans would be the perfect for that, and there are already way too many humans in the game. Making Vastayans similar to humans is borderline boring.
Also, if Sett is half Vastayan half Noxian, at least make him more furry, and not mentioning beard.
A common misconception is the vastaya are furries. Actually they are shapeshifters. And notably most of the creatures which inspired the early champions in this group are shape-shifters too. (A kumiho, the monkey king, a werecat etc..)
The vastaya are often in a shape that they have chosen both consciously and unconsciously based on tribe, environment, and personality. They can change shape depending upon the availability of magic, amount of time required for the change, and in the depth of their connection to their ancestry (vastayashairei). So a radical change that might take Rakan three days, totally exhaust him, and be hard for him to hold for more than a few minutes... well Neeko could do that in 2 seconds and hold it for several days. (Thus shapeshifting is a part of her gameplay kit and not a part of his, but in lore they both have some level of this ability.)
The vastaya generally avoid looking purely human or animalistic because it's uncomfortable and not ideal for fighting. (Xayah would find having a human foot about the same comfort and ease as you would wearing 8 inch platform heels, two sizes two small. You could do it, but you wouldn't want to fight those shoes and you wouldn't want to wear them for long either.) But yes this does mean they excell at spying and intrigue.
I didn't work on Sett but, one imagines Sett has some of this shapeshifting ability but it's pretty weak and probably not something he can control very well compared to his mother. (But also that looking more human is easier and more comfortable for him than it is for his mom).
Personally, I would love to see a more human looking Rengar canon skin and a less human looking Rakan and Xayah canon skins... cause it'd be cool to choose a canon skin before the fight.
Sett's appearance does technically make perfect sense.
Vastayans are part Vastayashai’rei, part human. That would essentially mean that Sett is basically 2/3rds human. It would make sense that the obvious animalistic Vastayan traits like fur and the such wouldn't necessarily manifest themselves as something that obvious in someone that is closer to a human and would manifest in another way (ie his ears, his size and his physical abilities).
Neeko, Xayah and Rakan covered in fur [sg-lux-2]
Nami covered in fur [sg-ahri-1]
In general I feel like most new vastaya are far too human looking. I mean they are shapeshifters, so they could really do something creative with them instead of humans with a few animal parts glued to them.
no
at least 
and 
look like what Vastayans you picture look like. i think Vastayans (at least modern ones) should look like Xayah and Rakan more or less as the Vastayans are already a cross between humans and the Vastayashai’rei
