I agree with everything you said, but how could little Eren have memories of the future if he didn't have a titan yet? I think that was just a directorial choice, to show those images and then Eren waking up and cry.
As far as we know, we didn't have a garantee that only Subjects of Ymir with a Power of the Titans could see his/her memories travelling through the paths. I think they are more likely to see their memories travelling through paths, but it's not impossible for others Subjects of Ymir I think. Eren Kruger said that sometimes, Eldian's (well, in this case, we're only talking about SoY, not the other Eldians bloodlines) memories travel through those paths, without saying it has to be one of the Nine Titan's memories.
Plus, I think we can consider the fact that "little Eren" received memories by someone who voluntarily send the memories, as many people think. It might be the future Eren "sending back" his memories to his younger himself, even tho we've never heard of people consciously sending their memories to someone else.
But yes, it could also be a directorial choice, from Isayama. In the very first episode, in this "long dream", we've seen a statue, wearing a suit first seen in the manga in chapter 95, released in 2017.... 4 years after the release of the first episode of season 1. Yes, we might consider this as transmedia foreshadowing.