I think just the system recognizing faces that it's seen before would be good enough. Entering by hand isn't too bad.
When it detects a new face, add it to the "seen faces" list, and let the user go back though that (sorted most recent at the top) whenever they like, to add names and maybe a short note like "met at party in LA". So you have to remember their name yourself but only momentarily until you can enter it into the local DB.
Whenever that face is detected again, it shows the info.
That way you can skip Internet connectivity on the device entirely.
When it detects a new face, add it to the "seen faces" list, and let the user go back though that (sorted most recent at the top) whenever they like, to add names and maybe a short note like "met at party in LA". So you have to remember their name yourself but only momentarily until you can enter it into the local DB.
Whenever that face is detected again, it shows the info.
That way you can skip Internet connectivity on the device entirely.