1. If the data is sensitive in any way, commingling it is dangerous and poor practice.
2. The FE and BE each need version tables.
3. When the FE opens, it compares the two version tables. If they are not compatible, then the app should refuse to open.
4. How you distribute the FE depends on whether the users are on the same LAN or are distributed. If they are on the same LAN, the simplest solution is to create a batch file that copies the FE from the master folder on the server to the local PC and then opens it. You create a shortcut to run the batch file. This method gives each user a fresh copy of the FE every time they open the app. If the users are distributed, you can use an FTP site from which they can download the updated FE. You have to create the procedure to do this for them as part of the batch file. Depending on what kind of FTP software you are using, it could be as simple as using a mapped drive.