Plex is great till you have to buy a PlexPass. Paying $75 to get functionality from a $35 device is absurd in my opinion. If you have a linux server running just install Serviio.
Are you using inSSIDer to check the other networks in your area? Channel 1 might just be too congested.
Here is the free version of inSSIDer Home, install it and post a screen shot of the Networks page.
Do a factory reset then redo your settings manually, dont back up from a file, and see if that helps. Some times when you go from a older firmware to a newer one, weird stuff can happen and a factory reset will correct it.
We should figure out how to do MediaWiki and share the database, 192.168.1.1/wiki , then we could edit and add our own notes from a base copy or something.
:)
Did you try blocking the mobile version of Youtube? Something like m.youtube.com
Also this: Two iOS 7 Features Parents Will Love
www.opendns.com which your router has built in support for, might be another option.