Lets see... if you had a wired extender or a second router and connected all the WIFI to it and had a plug in timer on the extender/router to power off at night....

Be sure you are using a good cable and power cycle the printer and router.

To replace a Comcast Gateway (Modem and router combo) first you need to go to the Comcast web site and look at the modems that are compatible with Comcast. You can get a Gateway or a separate modem...

Does it happen on both 2.4 and 5 GTZ? What I would try is change the SSIDs and connect one wireless device at a time to see if one of the devices is causing an issue. Could be an old device...

If it were me, I would contact support and get a replacement. Also consider a UPS. I use a UPS that has Automatic Voltage Regulation (AVR) for my router, modem, main PC, security system, and phone...

By chance did you use port forwarding and IP address reservation for the play station? If so you may be able to see it there or from one of your backups. Also do you have the original box the PS came...