Part of the Furniture
There is no way you need four routers in a ~645 SqFt home. Unless the walls are concrete or similar, drop the need for APs.
A single connection will be superior to what you suggested previously.
You may still leave the slower connection for failover WAN mode though, for the peace of mind.
The FTTP connection is highly recommended over the cable modem, particularly where latency is concerned.
Taking the size of the home into consideration and the assumption that the walls are not concrete (until they are proven otherwise), the recommendations above are certainly overkill for a home network with wireless WiFi being the preferred connection choice and a single network throughout.
Multiple floors plus basement, garage, etc more than 1 AP may be needed/warranted.
We've already established we're taking about overkill here