1950s-1970s Cat dies, goes to heaven, sent back to do good deeds. Repeat.

Pretty sure the cat's name is "Magnificat."

Could be "cozy" adult, but most likely junior. A chapter book, and very sweet in tone. The cat keeps kicking it, and getting sent back to earth to do good deeds until it either does a good enough deed, or runs out of lives (this isn't for me - it's for a library patron, and they couldn't remember).

What we know so far:
It isn't the Magnificat where the cat lives in the churchyard, that's too new.
Pretty sure it isn't The Three Lives of Thomasina, but they're working on that now, and will get back to me.
Most assuredly isn't The Cat Who Went to Heaven - that's a Buddhist fable.

Any ideas?

Nor the novella by...rats. A fantasy author, female I think. Published as a little tiny book. It's only maybe 10 years old, though it does have a cat who came back to help...but not repeatedly. The cat's name was Magnificat (which is only discovered at the end), but that wasn't the name of the novella. Phooey! Now I'm going to have to list this as a question.

Ah, found it - remembered a unique word. No One Noticed the Cat, by Anne McCaffrey. Copyright 1996, so, yeah, not what you're looking for.

It can't be Gobbolino, The Witch's Cat, I suppose, since the cat never dies and isn't named Magnificat. Gobbolino does keep on doing good deeds and losing his home, though.

I'll pass on both of those anyway - patrons (like everyone else) are funny about what they get right and what they remember wrong. If anyone else has any ideas, please keep them coming, and I'll let you know if we hit it!

Magnifi-Cat by Carolyn Sheehan, 1975?

Probably not - that seems (via Amazon) to focus on the cat being in heaven - but sounds really good! I'll have to keep an eye out for it.

Magnifi-Cat touchstone fairy

Though, yeah, again - what's remembered and what's in the blurb may not match, even on the right story.

Magnifi-Cat it was! They remembered the cover, and after reading it, apologised for mis-remembering the contents.

I also got them to read the Anne McCaffrey one (which I had read myself and enjoyed, but didn't even think about when they asked) and they enjoyed that also.

Thanks very much to all of you! Always amazing!