Ok, I will give my best crack at this.
1.
802.11 Mode: If possible, can you set it Mixed 802.11n, 802.11g? With the exception of maybe the Iphone, all those devices should be able to connect atleast at G right?
2.
Enable Auto Channel Scan: Is there any reason you have a manual channel set in? Its sometimes needed, but usually Channel Scan is best.
3.
Transmission Rate: Unless your doing alot of networking from computers to computers via the wireless connection, setting the MCS to 10 or below is usually a good idea. Anything over that is overkill and hurts wireless range and dependability.
4.
Channel Width: 20/40 usually works better, atleast I have never run into a problem with it. Was this done intentionally? Since its not default.
5.
WISH: We might turn this off later, once I understand the timing of the problem and your usage habits.
6.
Short GI: Disable this. It might knock throughput down a bit, but if wireless interfence is a factor here, then the decrease in error rate is worth more.
7.
WPA Mode: AES is going to get you a boost in performance and security. I assume some of the devices are not compatible? Maybe the Iphone and Printers?
Last, try to give more detail on the problem?
A. Does it ever happen when the desktops aren't online? Or aren't on WoW atleast?
B. Besides going hardwired to the router, does anything else resolve the issue? Power cycle of the router? reboot of the PC? Disabling and re-enabling the wireless connection?
C. Are there times when the desktop lag or loose connection when your not on your laptop?
D. Are there times when all computers loose connections?
E. Has this problem been occurring since the setup of the network? Or does it coincide with the addition or a change to the network?
F. Last, what are your Network Stats found
Here