Mari would be terrified of Kojo π Well, in step 2 at least. I think she wouldn't mind having him around in step 1-3-4. But Mari and he could get along in step 2 if they started talking to each other by some miracle. As for Yu-Ming, get ready for the special "I don't know that I have a puppy crush" SPECIAL!!! She'd get along in all steps, though she'd be unnerved in step 2 due to her friendly personality (trust issues dearie π). I think they'd be friends basically, maybe lovers, but we'd be slow burning like requiemduo. Either way, she's gonna be compliant with both of them because they could both break her arm π
Kel would be kind of unnerved by Kojo, but not enough to try and talk to him (and be a little annoying), they would be acquaintances in step 1 due to Kojo's grumpiness and Kel's somewhat cold nature with strangers. Other than that, they could get along on the other steps. As for Yu Ming, yeah, they'd get along, even in step 1. Natural besties over here π. He'd have a little puppy crush on both of them, as he does with most of his friends.
Elias is well, same as Mari. Utterly terrified of Kojo. But at the same time, he trusts him due to his position as Vice President, and they MIGHT be able to get along in Step 3-4 if someone introduced them or something. However, they won't get along in Step 1 due to Elias being a bitter boy and stuff. For Yu Ming, yeah, she's looking out for that dude. They might not be able to get along in Step one, BUT Yu Ming would make sure Elias was ok, and healthy :3