When I'm naming characters in a book, I like to browse sites like Behind the Name. Especially with BtN, it lists name meanings, origins (if known), and variations.
Mary - Her name could mean "wished for child" or "beloved." Once you read the part of the book on how she was born, you'll understand why I chose that name for her.
Carter - It means "one who uses a cart." (Duh.) But I chose to name him this because he's a vessel for the possessing thing. Cart? Carry? Get it? Yeah, it's not as clear cut, but I didn't want to name him "Potter" or "Tea cup" or "Gravy Boat."
Colette - Mary's mom's name is a derivative of Nicolette, is a feminized version of Nicholas, which is made of two words that mean "victory" and "people." Mary's mom is inspired by several stories from different women I've encountered over the years who have been victorious over many struggles. I hope the choice for her name honors them.
George - His name is made up of two words meaning "earth" and "work." George was a farmer when he was young, so that's why he's named that.
Sienna - She likes Italian things, so she's named for a the Italian town Siena, which is known for the orange-red colored clay there.
David - I didn't really name David's character because of the meaning. I named him because David is my brother's name, and I wanted to name a cool kid after him.
Scotty - This is another character I named not necessarily for the meaning, but for a person I once knew. Scotty had Down Syndrome. A few years ago, he went to sleep one night but never woke up again. I wanted to remember him in this character.
Mayim - Means "water" in Hebrew. Read the book and you'll know quickly why I named her that.
Phos - Means "light" in Greek. I won't tell more about this character here, but consider the fact that "light" exists in different wavelengths, not all of which can be detected by the human eye.
And that's it for now! Release date is coming up fast!