I have at least 100 different varieties in the ground, some as long as 13 years, and I can tell you honestly, what was cold tolerant one year, dropped leaves like a bad habit the following one or two years later or three years later. No way to predict. Yellow Excurrens, one of the toughest, went through last winter as bare as an empty hat rack. This year, they're thriving. Dreadlocks drops leaves completely if you walk past it with a cold beer and yet this winter, it's full of beautiful new growth. King of Siam, on the north side of the garden and unprotected, has never shown cold damage. Norma is the same. Thanksgiving, right next to both of them and in the ground twice as long (9 years) sheds leaves every winter.
There's no science to any of this. Your Crotons are, as mentioned, all the exact same species in the exact same local environment. It's all a matter of micro climates, cloudy days, and whether or not some passing raccoon took leak on the main trunk of the Gloriosa or the Thea just before it turned cold. Remember, Codiaeum variegatum is in reality a small tree that's deciduous north of zone 11 in both cold and drought. Gee, doesn't that sound like a Florida winter?