Clay: I think he would be a caregiver, but as a little he would be sweet, energetic, and still food driven. He would be more of a big brother, likely close to a toddler-ish age.
Tsunami: A little princess, demands sweets, treats, and every goodie that her siblings get. She's kind of a brat, but after she comes out of headspace she gets apologetic and embarrassed.
Sunny: Baby! She's so tiny when she's little. She can caregive of course, and is a good mama, but she's also a precious tiny dragonet. She ranges from almost newborn to a few years old, and her energy varies with the age.
Starflight: I don't think he would regress much, but if he did, it would be more trauma and stress based than "just for fun." He's very quiet, and tends to get scared easily and will hide. You can lure him out with promises of cuddles.
Glory: Also kind of a brat, very similar to Tsunami in many ways. She will take a lot of naps, somehow more than usual. She also loves being fed fruit and making a nest of stuffies and blankets. She can caregive but is usually more little.