Hi everyone.
What if Cedric's family had accepted the Triwizard award money from Harry or Fudge had decided not to give the award money to Harry? Harry would never have been able to give Fred and George the investment and they might not have been able to start their joke shop. That would mean no Peruvian Instant Darkness Powder and possibly no successful Death Eater infiltration of Hogwarts in Book #6. That would also mean that Ron wouldn't have been accidentally poisoned in Book #6 and the intended victim of the poison might have died.
(I like looking for minor changes in the story line that lead to major changes in the way things turn out.)
What do you all think?
I think the storyline changes you mentioned are likely. WWW as we know it in the books probably wouldn't have come into existence, ie. they wouldn't be able to afford to drop out of seventh year, open a business in Diagon Alley, etc.
However, they were already inventing things before they got the money, so I think it's likely the business would exist in some form. Maybe being built up as a mail order business for years while they work other jobs (depending on whether they survive the war; if we're looking at a butterfly effect kind of thing, maybe something else goes differently and they both live, George dies instead, etc.).