Help me find this book

Hello, I've asked so many people and I just sound crazy.

There's this book I read as a kid but I don't remember too much about it or the things I do know about it don't help me find it.
What I remember:
Girls dad is in war and they are living with grandparents (older sister younger brother) the grandma gives the child a trinket, (scissors that can cut anything) they go to this mansion meet 2 other kids (or more) the mansion has hidden tunnels, the girl tries to collect more trinket, she gets a cat trinket from a barn boy or something. The woman that's looking after them turns out to be a robot or something, bur she carries around 2 charms on her belt. Pretty sure there was a mansion on the cover, first or second page had a picture of all the trinkets and what they did I think?? Pretty sure there was 7.

I know it's all a mess sorry but this is all I can remember. It was so many years ago now, it's a jumble. Please help me find this book / give suggestions on what it could be.