My youngest is about your daughters size, she learned to roll with a Pygmy 13, was the first person under 30 to paddle the CLC14 when the water turned warm a few months after it was introduced. The LT16 and Ch14 both have have the same sized coaming as your Ch17. Stability is a high priority with maneuverability less important although at low angles of heeling they turn fine. She may find the 17"x31" coaming a bit big if waves become part of the paddling environment. The AT14 will be easier to turn than the Ch14 or LT16 as well as respond to paddler skill better in waves/wind. The AT14 is between those two for displacement. The LT16 sits the same depth in the water for a 200lb person as the standard 16, in other words it's a high volume hull shape with a low sheer.
The Shearwater Merganser 16 will be faster than the LT16, AT 14 and Ch14, it'll also go together quicker as a kit. Displacement is similar to the AT14.