Okay, these ones is really up to interpretation so let's see what I can do.

RACE

Lloyd- Honestly, his whole family strikes me as Japanese but I mainly imagine him being white. So I guess Japanese/American?

Kai- Filipino

Jay- Okay so Cliff just LOOKS French, am I the only one that sees that? Yes I am. He is a pale boy in my eyes though.

Nya- Filipino

Zane- I imagine him being really pale as well. I guess Swedish/Danish/whatever Northern European country.

Cole- Again, Lou just looks English and/or Hispanic to me for some reason. I can't explain it, really...! So basically that for Cole.

Pixal- Just like Zane, she would be from a Northern European country.

EYE COLOUR

Lloyd- Used to be red like Garmadad, now are obviously green.

Kai- Green

Jay- Blue

Cole- Honestly, I saw this really cool fanart of him with purple eyes, but hazel is a good alternative.

Nya- Brown

Pixal- Green

Zane- Pale Blue

GENERAL BODY STUFF

Lloyd- The third shortest of the boys, just above average in the rest.

Jay- Shortest of the boys, surprisingly skinny. Also, I always laughed at the 'strong arms' headcanon but now that I see it the dude has lifted and carried Nya at least two times with no problem like dang.

Kai- Third tallest of the boys, just a tad below Cole. Just fit in general, I guess. His hair gives him extra height.

Cole- Second tallest of the boys and buff as H E C K.

Zane- The tallest and slimmest of them all. He is not so surprisingly strong.

Pixal- Slightly less tall than Zane, though still surpasses most of the other Ninja. She doesn't have much muscle, though that's just because it isn't shown on her design. She could probably lift a car with one hand.

Nya- The shortest of them all, though not by a long shot. She's a bit... curvier, I guess? I don't know, really, but I do know that she has some muscle and she's not afraid to show it off.

So basically, in terms of height:

Nya<Jay<Lloyd<Kai<Pixal<Cole<Zane

Anddd that's it for the basics. Feel free to recommend any categories!

C ya!