The Kinesis "contoured" design with thumb clusters is almost 30 years old, and itself was a clone of the Maltron design - so I think it's accurate to describe the Ergodox as a clone of the Kinesis.
Seems to me like the Ergo almost exactly cloned the thumb cluster, and the Kinesis 360 almost exactly cloned the Ergo split design. They are clearly both drawing inspiration from each other, and there isn't one "clone"