Who would win in a fight?

Was bored, so I imagined a grand battle royale between these so-called "child geniuses". Fist fight. No weapons allowed.

Who wins in the following match-ups:

1. Ryan vs Arnav
2. Vanya vs Selah
3. Chancellor vs Tanishq
4. Claire vs Katherine
5. Yeji vs Gianna
6. Jaden vs Jason
7. Alexa vs Jenna
8. Izzie vs Iris
9. Drake vs Graham
10. Binyamin vs Sam


My personal take:

1. Ryan would beat the crap out of Arnav and his defeatist attitude. Ryan has had to fend off his petulant older brother, and he's shown strength as a fast swimmer. He's also had to build up toughness due to the rigors that SherryGODDESS has put him through. He'd win in a fight for sure.

2. Selah would crush Vanya. Though Vanya has the height and reach advantage, Selah, while powered on a sugar high, simply has too much energy and bulk for Vanya to overcome.

3. Close one, both gangly skinny kids, but Tanishq I think would eek out a victory, though it'd be a hard-fought one.

4. Katherine slaughters. Claire is too naive and emotive, while Katherine was a calm and collected stone-cold bitch, the true HBIC who would never suffer fools that dare to also get perfect scores or tie with her.

5. Gianna might actually take this one. She's seems scrappier than Yeji.

6. Likely a tie, but maybe slight edge to Jaden, since his paleo lifestyle and diet might give him the boost he needs when it's clutch. Though Jason I believe is slightly taller and has longer reach.

7. LOL Jenna punches Alexa's lights OUT. She's shown she's got the rage and temperament to do just that, what with her punching the walls whenever she's pissed off and all.

8. Izzie showed she was way more bombastic than laid-back yoga Iris. She even challenged the judges on her very first round, telling them to back the eff off with those questions that weren't in the study packet! She has the gusto to ignore pain from any potential hair-pulling and eek out a win.

9. Drake would backhand the crap out of Graham. Not even his god can save Graham from Drake's strong tennis arm after all those hours of practice Drake has put in.

10. While Binyamin has learned some self-defense moves from his ex-Israeli military special Ops dad, I don't think they'll prepare him for the sheer level of psycho batsh!t crazy Sam will bring to a fight. Sam catches Binyamin by surprise, and then proceeds to GO TO TOWN on his ass. 

Just my predictions.
Whom do you think wins these match-ups?