I'm going on the record that I run our ROKU wireless, with the wireless remote. I have exactly one of them and it puts itself on the same exact channel as the wifi access point it is connected to to talk to the wifi remote. The two signals constantly interfere with each other on my wireless, and I have only 1. Looks like you have 3, so maybe start with hard wiring those, even if only temporary, to see if it helps with the wifi problem. If it does, then you probably need to have someone come run a wallplate for those devices at least.
When a ROKU is hard wired, then the device will pick an unoccupied wifi channel to talk with the remote, but it must only have a single transmitter because if you are connected wireless it stays on the same channel and puts out mad signal.
When a ROKU is hard wired, then the device will pick an unoccupied wifi channel to talk with the remote, but it must only have a single transmitter because if you are connected wireless it stays on the same channel and puts out mad signal.