In which scenario do the different court systems in the U.S. interact properly?

• A West Virginia woman was driving across the country on vacation and caused a traffic accident in Nebraska that resulted in a personal injury tort claim. The case is tried in Nebraska, but the state court judge applies West Virginia law, since that's where the defendant is from.
• A New Jersey resident is sued by an Iowa resident. After a trial in which the New Jersey resident vigorously defends himself, the Iowa state court finds in favor of the defendant. The Iowa resident then files the same claim in a New Jersey state court, which dismisses the case.
• A convict on death row in Texas sues, claiming that the death penalty violates the prohibition in the Constitution of cruel and unusual punishment. The federal courts refuse to hear the case, because the complaint includes questions of Texas state law.
• A Colorado man is a defendant in a personal injury lawsuit for an incident that occurred in New Mexico when he was under the influence of marijuana. When hearing the case, the New Mexico judge applies the laws of Colorado, where marijuana is legal, rather than New Mexico law, which criminalizes it.