Greybeard

Are you using the Electronic Shutter?

Yes agreed - the easy answer is to increase the maximum ISO limit

Perhaps you could post some problem examples - SOOC with EXIF metadata intact - I find noise well controlled at 6400 ISO - unless you view at 100% and get close to the screen

This only changes the card selection in View Image mode - card used for Sequential data storage is independent of the card used for viewing image

Bluetooth Low Energy is designed to be on all the time - when you think about all the devices such as smart watches with small batteries that use it there can't be much impact on battery life.

Works OK on the XT-2 and according to the X-T20 manual and specifications its available on the X-T20 - just not as wide a range as when shooting stills: http://www.fujifilm.com/products/digital_cameras/x/fujifilm_x_t20/specifications/

And (at least on the X-T2) you can customize the rear dial press action (look at the Shortcuts section of the manual under Function Buttons)

Yes - and Fuji considers continuous bursts to be a form of bracketing (and marks them in the same way) so its tricky to use. I tend to leave the camera permanently on CL so every file gets marked as using Auto Bracketing.

This can be done on a computer after the files have been uploaded if you don't mind doing a little scripting. Information about the bracketed sets are stored in the EXIF metadata.