The username will not display as the only information the client sends across is the matching encryption key during authentication. If you want devices to display hostnames, then you have to join them to your domain, then use EAP with machine based authentication. For non-corporate devices, I would suggest you use EAP-TLS. However, for a small network like yours, I would rather stick to using pre-shared key authentication. If you had Cisco Prime Infrastructure, it would tell you not only the type of device connected (which WCS can also do), but other information such as the device operating system, e.t.c.
Like I mentioned earlier, you have a small wireless network within a building, so no need buying Cisco Prime, however going for EAP authentication method is your choice.
