I love how much of a character subversion Scratch is. Usually when you have a grumpy character it takes like 2 seasons for them to even admit that they even like the other characters. But like. Scratch admits that Molly is important to him in episode 5, and before that he becomes genuinely protective of her all the way back in episode 2. He goes soft fast, and he doesn't even deny it. He makes regular shows of affection to all of the McGees and is just happy to vibe around them. Sure, he's still grumpy a lot of the time (that's just his personality), but that doesn't change the fact that he's "McGee-Adjacent."
And MOLLY. She's optimistic to an unrealistic degree, but you actually get to see the realistic negative traits that would come from someone that unrealistically positive, to the point that, paradoxically, her character feels more realistic. She's a headstrong girl who wants to push for everyone's happiness, but that can ultimately cause just as many problems as it solves. She doesn't make compromises, even when she should, and she refuses to show negativity (most famously exemplified by her "Everything is Totally Normal" song).
Together, they cover each other's weaknesses while absorbing each other's strengths. Molly makes sure Scratch gets out there to actually DO something with his afterlife every once and a while, and Scratch makes sure to get Molly out of danger when her do-gooding goes too far.
TL;DR: Show good.