Attack on Titan: Shingeki no Kyojin

[Y]

That is the part my question related to. Either young Eren was a masterful, sociopathic actor OR older Eren did influence his earlier consciousness.

Neither one happens. Eren is influencing the decisions of the Titan that devoured his mother via the Paths. It has nothing to do with sending messages to himself. He cannot send any messages backwards to himself because he doesn't remember receiving them. We have access to his internal monologue, so we know he never received any messages from the future.

[DarthEnderX]

I just realized...wouldn't all the Wall Titans also have turned back into normal people?

Shouldn't there be, like, a million people just standing around all over the world?

[Buffalobiian]

That would make sense.

[neflight86]

Maybe they were puppet titans like the ones Eren spawned (prev gen 9 shifters) that only moved according to his will; just made by Ymir?