Are you sure that your factory resets didn’t revert to the original firmware?
I’m struggling to understand why rebooting your router would affect the ability to view video files.
If your MyCloud is connected directly to the router, then a router reboot is likely to have caused a MyCloud reboot (the MyCloud seems to to a reboot if its ethernet connection disappears, and then re-appears; putting a switch in the way means the MyCloud is unaffected by router reboots).
If the MyCloud rebooted, any settings you had made via the Twonky interface (port 9000) would have been lost (good integration, eh…?). You can prevent this with some use of the
/CacheVolume/user-start file on the MyCloud; see the Twonky FAQ for details. If you have a Gen1/v4 firmware device…
So it might be worth having another look at the Twonky UI, to make sure that your TV and Blu-Ray are being detected as the correct type of media receiver.
It’s also worth making sure that your TV and Blu-Ray are still connecting to the server in the same way they were before the router reboot; it may be possible for them to connect either by DLNA, or by a file server protocol (e.g. SMB).
Bizarrely, these devices often have entirely different media playback facilities for different media sources (check out the user manuals to see what file formats are supported via DLNA, and what are supported via USB; they are frequently not the same…). This smacks of entirely different media clients for DLNA and USB or file server access. Not a great example of design; just bolting source-based media players together, rather than integrating the sources, and then using a common media player…