For example, with wayward souls, will I still have the progress I had before I backed it up/restored it, or not?
If you back up to iCloud, yes you will. If you back up locally, you will if you also back up your apps to iTunes.
I'd use ifun box to back up the save files separately for games that you've put a lot if work into, like wayward. Then If the very worst happens you can reinstall the game and drop your save files back.
