You can go to the account tab and then click on Firmware upgrade to see the status of the firmware of all the devices. This is usually to do a bulk upgrade but it’s also an easy way to see all the firmware upgrades available.
I made a more specific topic regarding displaying the battery life on the home screen like one of your suggestions. However, I can merge it with your item to garner more votes if needed.
I’m not sure what you mean by re/calibration. Which devices require this?