Is there a version of SafeWallet available for SAMSUNG S6 and how do I move existing data from a Windows Phone (Windows 8.x) stored in Dropbox to my new S6?
There is a SafeWallet application but I don't think it's the one you're referring to. It's actually in Chinese. The version of the software you have mentioned is not available on the Play Store.
As a recommendation, I would install LastPass because it successfully replaces SafeWallet and provides features and cloud storage: https://play.google.com/store/apps/details?id=com.lastpass.lpandroid
Alternatively, try Keepass on Android: https://play.google.com/store/apps/details?id=com.android.keepass
