Currently I have several Roku Express that as you all know uses a IR remote. I’m looking at getting a Roku Streambar and from what I’m reading it uses a RF remote. Will the Roku Streambar’s RF remote work my vizio tv that uses a IR remote for mainly power on and off.
If I'm understanding what you're asking, the TV controls on the remote that comes with the Streambar should control the power and volume of your TV. You'll be prompted to set it up when you initially set up the Streambar.
Streambar remotes do not control tv volume by IR, and initially tv power either. It controls it be hdmi-cec, for it to work the tv must recognize the streambar as cec device. So there is no programming needed to get the volume, no need for tv brand selection, since ALL tv brands respond to the same cec signals, if it has that feature. When the Roku soundbar was release you couldn't select a tv brand, it wasn't needed they thought. But later it came apparent that some tv brands couldn't come out of standby from cec signal like they can for a IR signal. So roku upgraded the settings to allow you to program a tv brand strictly for power in those cases, the remote had IR on-board already so it didn't need a new remote.
Also the Streambar will respond to the same roku IR remote that your express uses, thats for roku commands.