Since OfflineSurveys version 1.13 (released 2016-05-02) you can now share any Limesurvey survey you have cached at your Android device. Just click the share icon:
You can then send the whole survey as .LSO file to any email address(es). The file will be fully encrypted, also username and password will be encrypted in the database.
Once someone has received such an LSO file they just need to select “OfflineSurveys” to open the file: