The more I thought about this, the more clever I thought it was. I'm a graphic-oriented person, so what I think you came up with looks like this:
More or less anyway. You weren't sure if the second splitter needed to be MoCA 2.0 capable or not, but I'm fairly certain it does have to be. Otherwise, the upper band frequencies needed by your second ECB6200 might be "filtered" out.
My setup: 75/75 Mbps; Linux router (2x 1Gbps ports) + iptables; Netgear Orbi x 2