Ease through the Body

I am about to draft these off for Tildy. I would like them to fit now, not too bothered about growth room as I have Trixie to hand them down to. Her height puts her in a 4 but her waist puts her in a 12-18 mnth. Her hip aligns to the 18-24 mnth. I am leaning towards the size 2T with the length of a 4 but will they be impossibly baggy? Is there anyone who has made the smaller sizes that can help me? Thank you!