"Dich" vs "dich ein" what's the difference?
What does "redet auf dich ein" mean?
Does it mean someone is talking (i) to only you OR (ii) to you, telling you something OR (iii) speaking to you one-on-one ?
Also, does "jemand redet auf dich" have the exact same meaning as "jemand redet auf dich ein"?
"Jemand redet auf dich" without the "ein" doesn't exist. The verb is "auf jemanden einreden".
It's a figure of speech about talking a lot to one person, in order to convince them of something (and not wanting to stop until they are) or just talking a lot and not letting them get a word in.
There's also "jemanden etwas einreden", which means to convince someone (even oneself as "sich etwas einreden") of something that is not true.
"jemandem zureden" is mostly used to calm someone down or convince someone (calmly) who believes a false thing of the truth. It's often used as "jemandem gut zureden". If it's not done in a calm way it is "jemandem etwas einreden".
Actually reading your well explained list, I asked myself how someone would translate the word einsagen in English.
There are in many languages the word souffler (from French) - soufflieren.
But this is mostly used in the Theatre. Einsagen is used e.x in school when you don't know the answer and somebody whispers it - so only you can hear it.
I looked it up but nothing convinced me. LEO doesn't even have this word in its database.
I am from Austria but I am pretty sure that it is used in Germany in the very same way.