Curate, connect, and discover
two things i think are REQUIRED for a buck and eddie getting together arc:
eddie has to choose buck. this is necessary character development for both of them (and also for me because otherwise this will be my supervillain origin story). eddie needs to choose something that will make him happy rather than denying himself habitually as punishment, and he needs to admit what he wants. buck needs to be shown that he's wanted, that not only has eddie chosen him specifically but eddie knows him better than anyone else in the world and has seen him at his worst and loves him for it. he doesn't need to be on his best behavior for eddie, ever.
after they kiss buck needs to freak the fuck out and run to maddie or hen or bobby and go "I KISSED EDDIE. I AM A MONSTER. JAIL FOR BUCK FOR ONE THOUSAND YEARS" and then when they make him go through the sequence of events that actually happened they're like "uhhhh it sounds like he kissed you, bud. did you just blank on the whole part where he said he loves you and tenderly caressed your face?" but buck is still breathing into a paper bag.
bonus requirement: eddie needs to kiss buck's birthmark.