Yep, they're all Zurumon. Just thought it'd be an interesting dynamic to start off with and then show them all digivolving down different routes, further highlighting the non-linear nature of digimon evolution.
Digimon 1: Golden-Eye (Zurumon)
Personality: Golden-Eye, likes to rush in and check out new and interesting situations. They like jumping out and about at new people, and love to see new places. They especially love to go and find new tricks or cool things to impress others with. Whenever someone is in trouble, Golden-eye is quick to report back to try find ways to help them.
Digimon 2: Phantom-Pain (Zurumon)
Personality: Phantom-Pain, tends to keep to stray away from new people. They’d rather stay among people they know and keep them out of danger. They’re willing to put themselves on the line without missing a beat for their friends, and do their best to keep them away from trouble. When people do take the time to listen, it can be rather crazy to peer into Phatom-pain’s mind. They can’t help but see the world in weird new lights or possibilities. A broken bridge? Why not turn it into a massive looping slide! A mountain, that could be a large ancient Digimon that’s actually just asleep. A tree? No wait that’s actually just a tree, but it could turn into a giant totem pole if someone carves into it.
Digimon 3: Bone-breaker (Zurumon)
Personality: Bone-breaker tends be the one to cause the most trouble. They have a constant fun and playful attitude about them and look at the fun bright sides of matters. That being said, they love to fight, though often misconstrue it as play-fighting. If it looks fun to fight, and if they can get away with it without getting in trouble, Bone-breaker is going to fight it. Whether they win or lose, they don’t particularly mind, just so long as the fight was fun and entertaining. They, tend not to take whatever trouble they get into, too seriously. The only exception is when their fights affect someone else or cause massive trouble for others, when it starts to wear them down.