Caught in a time loop there, huh Bob? lol
I see what you're saying but it doesn't make sense to me. Here's why:
Jack & Co are in their present. But if Jack decides he's gonna explode Jughead, where previously he hadn't, that means that he had never before gone into the Others camp to ask for help. Which means that Richard and Ellie never helped Jack. But they did, we saw them, so... Richard, Ellie, etc., they all have to make decisions having to do with Jack and Jughead where they never had to make those decisions before. If Jack & Co can effect the outcome of The Incident, then they MUST effect how the other people on the island react to it.
Right? 
Yes, EXACTLY!! But none of that happens until they do it, because it's their present. Stop seeing it from the future and looking back at what HAPPENED, and start seeing it from the present and what's GOING TO HAPPEN.
Well now I'm at confusion X 1,000,000 cause I thought I was contradicting your first post and then you agreed with me, lol! So... "whatever happened, happened," isn't actually happening? Is that what you're saying? That they're changing how 2004 is gonna work out for the island? That's the only way I can make sense of this... I think. 
YES!! But they haven't done it yet, so nothing has changwed yet. Sort of like how Desmond suddenly had the "memory" of Daniel telling him to go find his mother. Desmond didn't remember until Daniel told him.
I always hated that scene because no matter when Dan told him, it was always Des' past. He told him 3-6 years ago so no matter Daniels perspective of time, it was still Desmonds past so he should have remembered all along.
I know so only Dan can evoke the memories of that time
