The recovery data is saved every 2 minutes but it’s used to restore information in case of a crash. A possible quick solution for the next version could be to keep the data for a while (e.g. a month) with a special “closed” file in the session folder so it’s not listed in the “Recover Lost Sprites” button at the very beginning and add a new option to listed all sessions (even the one closed correctly) from some menu/option.
My recommendation is that you can use a service like Dropbox to keep track of each version of your files automatically.
No these files are the files storing the configuration of the original file (e.g. grid settings, etc.)