According to Poyo Ride, he wouldn't roast a Hot Dog over a fire, though he would Microwave one and eat it.
Unlike the last Splatfest comic, the bottom message is not shown, saying to vote *side Poyo Ride Picked.* This means the comic does not outright reveal which side Poyo is on. However, if you compare this to Comic 64, the last Splatfest Comic, it's pretty obivous that he is on Hot Dog, unless youre a retard or haven't looked at Comic 64.
The person yelling in the Marshmallow side is confirmed to be Yellow Kirby.