It sure is! The monochrome sensors are also great for narrowband imaging, where the filters let through one specific wavelength of light (like hydrogen alpha) which lets you do false color imaging.

IR is basically the same. Here’s the page on JWST’s filters. No clue about xray scopes, but IIRC they don’t use any kind of traditional CMOS or CCD sensor.

At least for astronomy, you just have one sensor (they’re all CMOS nowadays) and rotate out the RGB filters in front of it.