A:AnswerNo, there is no way to write to media directly from the Roku. The premiere doesn't have a usb port. You can read media from an SD card on the premiere+.
A:AnswerThere are several 4K channels in the ROKU lineup.
If you have a 4K TV/monitor that is specifically 4K, you should be able to set the fps depending on what the channels support.
A:AnswerI am not sure since the TV's we used this Roku on are not the Smart TVs. We are planning to purchase another one for our 55" Smart TV and I will read about it then to see if it is compatible.