The end scene of Furiosa definitely has a large time jump. There was enough time for a tree to grow over Dementus. Which at a minimum is a few years. I would consider that to be enough time to rebuild gas town and bullet farm. Not to mention the implied time jump based on the her age difference. I think all the other minor discrepancies play into the idea that tales passed down by oral recollection will result in changes. The movie even implied that with the narrator talking about the different version of how people recall Furiosa killing Dementus.
I take all of it to mean that the major plot points are events that happened but the details, actions scenes, etc can be embellishments of each story teller.
True she didn’t have to be there but we were shown her picking the first fruit from the tree and then it cuts to the escape with the wives. Regardless of the tree though, the age difference explains the necessary time jump from Furiosa killing/catching Dementus to Furiosa making the Fury Road run.