My opinion: Don’t buy a new/factory Dell SFF or Micro for a homelab unless you’re experienced. If you’re new you need to get a feel for exactly what you what you want. And that’s important because these machines are expensive on the Dell site and you can get solid machines for some fraction of the price on eBay.

I don’t know your aim but if you want performance: you have two PCIe slots so you could put a 10GbE card in each Optiplex then switch with a Mikrotik CRS305.

That draws a lot more power than I would have expected. Are you including literally everything in the diagram in that number (ie including cameras etc)? Also, do you happen to know how the power consumption breaks down on a per machine basis?