Toyota would only have a minuscule chance at the constructors championship even with a 1-2. It would extend it to Bahrain, but then, even if they 1-2'd Shanghai and Bahrain, Porsche would have to not show up in order for Toyota to win.
They award points for 75% of the race iirc, so both Porsche's would have to dnf? That hasn't happened all year, but strange things can take place!
About Lopez, he was out of two races at the beginning of the year. So his experience with traffic is lacking, but he was very fast. He just needs more time. Unlike Lapierre, he hasn't had LMP2 or even GTE experience.