Wild Kratts/WMG

One of These Bros Is Not Like the Other.
Look at them. They're polar opposites. Chris is tan, brunette, and brown eyed. Martin is white, blond, and blue eyed. There are 3 theories here:

1)They're not really brothers. They're cousins, IF they're even related.

2)They're only partly brothers. One of their parents is different. It's either they have the same mother (half brothers) or same dad (step brothers). Maybe even 3/4 brothers (consult The Other Wiki for more details.)

3)One of them is adopted. Sort of ties into number 1, but to a different degree.

Maybe even a mix of them, maybe one of them is an adopted cousin or something of the sort

Aviva is Allison from Kratts' Creatures.
They look so much alike and do practically the same job. The only difference is that Allison was 15 and we think Aviva's at least 18 (but we don't know this for sure- it's never been directly stated she is, we've all just assumed it).

-They look the same height and weight.

-They have somewhat similar voices.

-They share similar physical features (same skin and hair color).

-They both serve(d) as the researcher and communicator for the Bros.

Although Koki mans the computer, Aviva does most of the talking on it, plus contacting them on their Creature Pods. The main difference between Allison and Aviva (similar names... hmmm...) are their personalities. However, we don't know what Shannon Duff was like outside of being Allison, so that's still up for debate.

However, since the rumor is that Aviva was modeled after someone from Chris' personal life- and we don't know if she was a lover or just a friend- given that Shannon was 15 in Real Life when Chris was 25... (But come on. If that's true, he waited the other 3 years. Chris isn't a scumbag!)

Extention of previous
If Aviva is Allison, then Koki could potentially be Ttark, and maybe Jimmy even Zoboomafoo. Koki and Ttark share a lot of qualities as well- Ttark was in the computer, Koki is on it. They're both snarkers Up to Eleven as well. Jimmy makes similar, but not the exact same, mistakes Zoboo would make.

Gourmand "LIKE" Likes Chris.
Gourmand is always chasing Chris. Gourmand has made remarks about eating Chris, in "Platypus Cafe" and "Raptor Round-Up". "Chris: *in the Peregrine suit* These wings were made for flying! Gourmand: Frying!

Chris: Flying!

Gourmand: *slowly and insistently* Fryyyiiing..."

Later... "Gourmand: *chasing Chris in the air* Here, birdy birdy birdy!"

"Raptor Round-Up"

Stalkers often kill the ones they love so that no one else can have them...