Well it said there that Mark gave the pendant to Lars or Gil i think? But when i played to Mark's route there was no flashback of memories, just a drawing of the pendant. Because of that i'm confused if Mark was a part of Walter's life when they were a child.
I think that's how it goes. I kinda put the pieces of his memories together.
"Lars"
Walter has a memory of Lars in the past. Walter was walking when he accidentally tripped and hurt his arm, Lars came to the rescue 😎. Lars treated Walter's arm, that was his first encounter with Lars.
"Mr.Parker" (or Parkie -that is what he was called in the past- Based on my research.)
Walter had a memory with Parkie too. When they met the first time after Lars treated Walter's wound in the arm because Walter tripped. Parkie is Walter's new neighbor and that was also Walter's first encounter with Parkie.
"Gilbert"
I think the memory Walter had with Gilbert in the past was the hide and seek part when Gilbert found Zac (and it seemed like Gilbert cheated xD). And also Coach Gilbert told Walter that they used to take a bath, only the two of them...alone, but yeah i think Zac still don't know what love is at that time 'cause he was a child (i think 5 years old) because it was 17 years ago and right now he was 22 years old.. ughh i hate math.
So Zac was 5 yrs. old
Lars was 12 yrs. old
Gilbert was also 12 yrs. old
Parkie was 13 yrs. old i think ( i don't have info about his character age. But he said he's older by 8 years with Walter.)
So far i have no proof if Mark was a part of Walter's past. Same with Anders.
And also there are still 2 space in the main characters. I think they will add more? Haha.
Correct me if i'm wrong at some part, this is based on my opinion hahahaha. ( I was totally out of topic lol )