While you guts vote, I would explain a ranking by worst to best babysitter because to show my opinion as well
1/Best: Lena
I'm gonna gives props to Lena because with her magic- maybe she might do some cute magic tricks or play with kids with her magic or something. Lena has light magic now and less dark magic mostly, just to remind you that. So Lena’s my best choice as babysitter
2: Dewey
I would say that Im okay with Dewey babysit kids, sure he has an ego and maybe reckless, but those flaws aren't that strong to not make Dewey stand out. Also he could be a fun for kids.
3: Webby
She would be fun and wild with kids, she can be like a big happy sister figure or some sort.
4: Violet
I don't she would be a bad babysitter at all, but there isn't special much of her to stand out, maybe a Woodchuck teacher, idk.
5: Huey
Why because I don't think Huey would handle all the responsibilities as Baby make noises or crying would annoy him alot and he might get exhausted and a headache.
6/Worst: Louie
Yes because for one, he is selfish and as considered the greedy one, he almost destroyed space and time before he saved space and time, reckless schemes, and he is less caring out of the Triplets despite he still has care. So he is the most I would fire first.