Flower girl gifts?

We got our flower girl (she was three then) a set of customized paper dolls that look like her and a book about being a flower girl.

We got everyone in the WP a gift including our flower children (both my niece and nephew wanted to throw the flowers).

Why wouldn't you get your flower girl a thank you gift? She should be thanked just like the adults in your wedding party.

I'm planning on gifting them necklaces of their birth stone

Yes, you should get them gifts to thank them, just like any other member of the WP. We got ours (3 and 4) a build-a-bear dressed like a bride and a small duplo set.

I'm thinking of getting her a doll with the matching dress she picked out

I believe it's really up to you if you want to. It's not required, but it's become very common. Most kids are too young to really care too much anyway.

I will personally be giving my flower (well, sea shell) girl an art kit as she wants to be an artist like her sisters. Nothing real spendy, but I know she'll love it

Yes, it's typical for the children in the WP to receive thank you gifts. Our FG and RB were both girls. One I knew loves loves doing big girl spa stuff with her mom and the other loves bath time and doing big girl stuff. I got them the "bundle of fun" from Lush, so they basically got a kind of play-doh soap that they could use to make their own bath bombs and then could take bubble baths. They were 9 and 4 years old.

My niece is 6 and we got her this from Justice. She's obsessed with Mermaids.

We ask ours to be in the wedding with a special gift (her dress) i also got her jewelry very similar to my wedding party