How do I teach my 6 yo decent freestyle?

So my daughter is 6 and is swimming on the summer team. She is a very good little breaststroker and has a powerful kick. However she uses a modified version of this kick on her backstroke and freestyle, but it seems to affect the freestyle far more. I have no idea how many times the coaches say and I say, "keep your legs straight"; "kick up and down from your hips"; "touch your big toes with each other", she STILL does this awful wonky breastroke kick action which slows her down and snakes her across the pool! So I'm now wondering if she's doing something mega-wrong with her pull and feels she needs to compensate on her kick? She turns and looks at the ceiling to breathe, but I thought that was pretty "normal" at that age, but otherwise it looks reasonable. She is also very competitive in the lane, wanting to catch up with whoever is at the front, so I have said that it slows her down when she bends her legs, but she still persists. Anyway if any of you more experienced in coaching littlies have any tips, I'd very much appreciate it.