Generally speaking they look good for the ideal situation. However, it is far more common to not be able to isolate the cable modem from the MoCA network. For it to work as pictured you need two coax runs to the location of the cable modem and router. Most homes only have one run to each room. You could place the cable modem near the utility closet but that is usually a pretty bad location for an access point. Most MoCA installed end up with a single coax network and the point of entry filter on the far left.

With regards to the point of entry filter in the second diagram: as noted in the image you do not the filter since the MoCA and CatTV network are completely isolated.

Sorry if this is not exactly an enterprise network post orz.

Gotta start somewhere right?