Apple Users

. . . . be networked with PC hardware just fine.

We have 5 Macs, three iPads, and two PCs here. We have our Verizon FIOS modem/router and all can connect to that. We then have an Airport Extreme (AE) and all can also connect to that. We also have two 1TB drives connected to the AE. The printer is connected to the FIOS modem/router but could just as easily be connected to the AE.

We store stuff on the two network drives connected to the AE. We also store stuff on the cloud, but continue to be wary of security so we limit the type of data we store there.

You won't need a server at all. Servers "serve" apps and data to networked computers. Let each MacBook stand alone, so to speak, loaded with its own apps and storing its own data. Use one of many backup solutions to move the data you wish to have in a safe place, and data you wish to store over to the network drives. Drives are so cheap that it ought not be an issue at all. Free standing network type drives are about a hundred bucks per TB. Buy one for each computer, if you like, and put them all on the network.