Bear with me on this:
DD2's pencil grip is not great. She's using a grip to try and modify it.
Her writing size varies wildly, even within a sentence (from very large to tiny) and where the writing is on the line also varies wildly.
I was watching her using her yoyo today, and she used the left hand. DD3, who is right handed and uses her right hand for her yoyo, has a good pen grip for age, and consistent writing size for age. I've excluded DD1 from my 'pool' because she has bendy, floppy fingers and isn't really writing yet.
DD2 also sucks her left hand constantly.
Is it possible/likely/probable that she is actually left handed, but has learned to write with her right hand because she was unable to use the left hand as it was in her mouth all the time?