Hi @JiiPee - I hope you don’t mind that I moved your post out of the Configure Style/Icon by Attribute Value post as it seemed to be a variety of different questions (and not all tied to the release post).
It looks like there’s a few big questions here, so you might have better luck breaking them into their own topics. It’s easier for people to read a topic title and see if it’s something they have experience with or are interested in.
Yes, you can choose the ‘Mode Picker’ option in the Location section. It shows a single icon with the current mode and when you tap on it you will be presented with a list of modes to choose from.
Is the request for the ability to configure different styles based on the ‘value’ of the mode? If so, please feel free to create a feature request. 
If the device reports units, then they should show up immediately after the value as you noted.
There’s not an official feature for prepending text in the footer, but it could be accomplished with a bit of creative Custom CSS. Might be a good question to post as its own topic or in the [WIKI] Custom CSS snippets, verified on SharpTools thread.
The data would have to be on the same device to be used in the Hero Attribute tile. As you alluded to, you might be able to use a custom virtual device to combine them.
Alternatively, you might be able to use variables to combine them into strings as you mentioned - probably a bit of nested IFs.
Feel free to create a feature request! 
Or if you have coding experience or know someone who does, you could accomplish it with custom tiles.