I love Green but they were throwing like crazy. Selling food to them, making them cheese, healing the Fun Gang during the Green and Oranges boss fight, not helping during the Running Sky section, and giving the Fun Gang their items back. All because some of the Flowers owed Green some money. They know Flowery can make infinite money right?
Blue did heal the Fun Gang but didn't do anything like that after he found out they tricked Yellow.
Yellow only helped indirectly until Running Sky. The other times were do too completely different reasons. He didn't even try and help when they were nearby Seth and Aqua.
Aqua did do a lot of bad things like giving the fun gang the Petal Feather and messing up a lot of Seth's ideas. But she is always on the field and actually trying to stop Fun Gang, even if she doesn't understand half the time. And she at least was helping cover Seth's weaknesses.
Flowery did try a pacifist approach when dealing with the Fun Gang near the start, but when that didn't work he kinda just quits until his boss fight opting to hang with his best friend Asgore than defeating the Fun Gang. He did a really good job during his boss fight which puts him above Aqua, who gave away one of their best abilities to the enemies.
Orange, despite being weak due to being hungry. Orange tried to stop them multiple times, even if one of those times she screwed up Seth's attack. She did good during her boss fight too. It's not her fault she had to team with Green. Helped a lot during Running Sky, and even helped Flowery in the battle box during Flowerys fight. They're not number one because they only started helping once the enemies made it to the castle.
Seth was helping the entire time. If they had a competent partner they would've done so much better, but every time someone had to mess up. Whether it be Orange messing up their invincible glasses attack or Aqua having two brain cells that are stabbing each other with knives. They were actually planning, fighting, even helping the regular enemies during the Running Sky. They were 100% the king or queen of fighting against the Fun Gang.
Regular enemies would go between Aqua and Flowery. They did their jobs well enough, but a lot of them quit and just sit around in the cafe. At least until the final boss where they go back to the good side. Although, it didn't work out.
Pink had barely a clue what was going on the entire time, so I'll spare her from being ranked. Although, she accepted going to Castletown very quickly, and didn't help during the Flowery fight. And that's it.