So far, this issue a flashback to Doc's younger years. A chrononaut is looking for Doc, but it seems he got the Doc a little earlier in his life than anticipated.
One possible answer to my question 1:
Adult Doc was seeing his younger self doing something before it happened causally. Adult Doc was watching the future, which is why he didn't remember it. It is new to Young Doc because he hadn't gotten old enough ride Sparklelord through the cave yet. I think it's time for another diagram for what I mean (yay!).
If the portal causes things in and around it to occupy the adjacent times and spaces, but centered in a "temporal position" between our Adult Doc and Kid Doc, they would pass near the portal at different times in their lives.
Edit: my paragraph before the image makes no sense now, but the one afterwards is closer to the way I understand it. What will really bake your noodle is space-time field the portal distorts is more than 2 dimensional like on the diagram, and is also moving, and changing shape! Wee!
THE GREATEST SNACK OF ALL IS BITE SIZED TWIX AND I WILL NEVER CHOOSE ANOTHER FOOD BEFORE IT IF GIVEN THE OPTION