I got this from the Fetch! With Ruff Ruffman website. Here's all the info on Marco from Season 5:

Pet profile:
Marco has three cachorros and four cats. He claims one of his cachorros will eat anything! Okay, one liver and pineapple bolacha, biscoito shake to go!

Sibling status:
Marco has an older sister, stepsister, and stepbrother.

Nickname:
Frongi, because it's part of his name

Food facts:
Some of his favoritos are Italian wedding soup, his dad's pizza, and broccoli. But don't give him spicy comida unless you have a fogo extinguisher handy!

Hobbies:
Video games, building things, skateboarding, acting, and listening to music...

I got this from the Fetch! With Ruff Ruffman website. Here's a little info on Julia from Season 1:

Pet profile:
Julia has German Shepherds named Lyra and Charlie and a bird named Punkin. NOT PUMPKIN, PUNKIN. His nickname is Puh-Puh. Lyra and Charlie just amor to go for walks in the woods with the whole family.

Nickname:
"Captain Hip," because she's so hip!

Sibling status:
Julia has two older brothers and a younger sister.

Scared of:
She's scared of water skiing. Julia tried it once and almost got up, but chickened out and wouldn't continue.

Unique talents:
Julia can drive her dad's tractor. She...

all right, from the poles on the cutest guy fetcher, Issac wins. so i'll tell you everything i know about him, starting with his last neame (its a really wierd last name, if u heard a diff. one like jay's one says that his last names Anderson, and another one says that his last names Brosnan)

Issac's last name is Bean. just to make this easier, i copied and pasted everything that was on his profile: link

Pet profile:
Isaac has three dogs, and he taught one of them to dance like a ballerina! But, Isaac would be really embarrassed to do a ballerina act himself! He does a mean moonwalk into English...

I got this from the "Fetch! With Ruff Ruffman" website. Here's all the info on gaio, jay from Season 3:

Pet profile:
Jay doesn't have a pet but he loves animals. He says he wants to have either a hedgehog or a dog. I don't know how hedgehogs could even be on the same level as dogs, but whatever.

Hobbies:
Bass guitar, lacrosse, skiing, hacky sack, karate.

Unusual talents:
Jay has a black cinto, correia in karate. I don't think that cinto, correia holds his pants up too well, but I'm no expert on that. Especially considering that I don't usually wear belts. Or pants for that matter. But as I was saying - um, you might wanna...