Okay, just getting real for a second, that is definitely a trick redefinition of "being there" to something other than what was originally being referred to. Kind of like if I stole a kid's lollypop, and when he complained, I told him that as long as he remembered the lollypop, he would still have it.
That's the key difference to the lollipop. Remembrance is not an observable side effect of lollipops. That tree I planted is. That person whose career I helped improve still has an improved career. Etc.
That's one of the two ways you live. The other one is the experiences you have. Sure, you can optimize for that, but as far as we all know it pretty much stops when you die. So I prefer option 1.
Yes it is, it's manifested in the physical re-arrangement of the kid's neurons.
As for not being there - you still are. You have touched innumerable lives, for better or worse, as you live. You shape those lives by what you do, and you live on in the effects you had.
No more HN or chocolate though. I'll miss chocolate.