Oh, and about megucas maturing earlier than normal girls, I do agree to an extent, but I also like to take things on a case by case basis, Iroha is a huge example of someone who matured much younger, and by the end of part 1, she becomes the political leader of Kamihama with the founding of the Kamihama Magia Union, with Yachiyo and Kanagi as her second-in-commands, which is a part of the reason I don't take issue with the age difference between her and Yachiyo, it has some nuance to it.
In the other hand, we have Felicia, who is completely a child with no signs of having even started developing towards having romantic interests, and has the dynamic with Iroha and Yachiyo of being their adoptive kid(something I believe Sana also has, and the anime highlights this dynamic by having Felicia and Sana share a bedroom, AKA, putting them on the same level), so in her case, I don't strongly ship her with anyone, though I still like to pair her with Kako with a "in the future" sense, they are both too childish to develop a relationship right now... but maybe if we could give them a year or two, so that puberty can proper kick them in the chin, they could be a thing.
Ultimately respecting who the character is, is something important to me, and I feel if you ignore who they are too much, doesn't matter how much two characters have interacted, it is just a crack ship, and while they can be fun in themselves, it is not something I would want to get invested in as I do with some other ships, so there has to be a nuance to things, and take things on a case-by-case basis like I said at the start.