A database is a database is a database. Doesn't matter what application is using it, creating the accounts, profiles, etc. As long as the information that is in the database aligns with what is needed by each application, it really doesn't matter.
If you want to use your app to write to the database, that's fine, just make sure all the information is there that xF needs (and in the proper format), or you're likely to run into problems, errors, etc.