Hi,

For information I installed Samantha and the tts software as above but it failed to show up under setup. Just " searching for...".
Later I installed google voice which initially seemed to fail but later (after reboot) seemed to have worked. After setting google as default voice it did show all the US google voices and also samantha, and everything now works, which is excellent.

This on Erisin android 6, 2-din head unit.