Is it really a celebration of family life when Moominpappa uproots the whole family because of his midlife crisis and sends Moominmamma into depression?

I would say yes. In my standards that still accounts for interesting-life-choices-but-safe-and-sane. But I grew up in an alcoholic family so realize my standards are likely slightly low-bar for what accounts for 'admirable'.

They come through it wiser and more in touch with themselves.

A family is a place where you should be able to also be something else than the ideal version of yourself that you’d like to show the rest of the world, something less perfect and more work-in-progress. Moomins lean heavily on showing how that actually makes their family stronger.

> They come through it wiser and more in touch with themselves.

Are you sure? Or is this just projecting the ideals we think childrens books are supposed to have? How is Moominmamma changed after the ordeal on the lonely island? - we don’t know, because the next book is about missing her and about how her absence affects the characters left behind.

The darker threads in the Moomin books are not hidden. It is all in plain view.

Like the squirrel which is too absent minded to seek shelter when the hard frost hits. Guess what - it freezes to death. They give it a nice burial though.