I think Cha-baek is fine. Others sound kinda weird... since they're names, i don't think there's any need to translate names by their meaning. ^^
And about the 2nd thing, i think 3rd person is okay for grandma since she speaks in a very cute and fluffy manner. But Idk about the mother. I think it's alright if it makes sense?
Anyways, Thanks for translating! I have high hopes for this series fufufu.