If you reflash with a FIASCO image, you won't erase MyDocs. To erase MyDocs you need to flash with eMMC too.

It is quite easy to reinstall apps. It will take time, because they will need to be redownloaded and installed. Might take an hour or two but everything automatically. However you might have to click a couple of times. Some apps bring up a window with terms of agreement and whatnot, and you will have to accept. Other than that, it does it by itself. I suggest you start the process while watching TV, and every few minutes check that the process wasn't stopped by some popup.