Tonys It is hard to say what exactly is happening in your system based on this information, but I will just list you all possible sources of people data so you can use it to figure out what is happening.
Tonfotos does not use registry to store any data. It only stores in its internal database (which gets deleted if you do uninstall on Windows), and also inside ini files and tnfp file (more about it here: https://community.tonfotos.com/d/186-version-150-people-data-synchronization). I guess you deleted all of those too.
Next, keep in mind that there is feature to store people data in XMP metadata inside files: https://community.tonfotos.com/d/535-version-1105-saving-person-data-in-xmp It is off by defult, but if you turned that on some time in the past, that data could be already written into files, and there is no easy way to clean it from there. That could explain what you are experiencing.
Next, if that was not the reason, Tonfotos can also read people informaton stored into XMP metadata by other applications, and it reads picasa.ini files stored by Picasa. So you might want to remove those too.
