Your first scenario is a little difficult to answer without details but for the sake of an answer, I will take some assumptions into consideration: In all scenarios, the driver is not speeding (traveling at a speed above the posted speed limit). If the light is green and the driver is not turning, this will likely be a no fault accident at best and a possible misdemeanor homicide at worst. This assumes that the initial pedestrian is crossing in front of the forward motion of the car and the light is green or yellow (and the drive cannot safely stop). A misdemeanor homicide occurs when a person dies as a result of another person's lawbreaking when the law that was broken was a misdemeanor offense (it's the Misdemeanor version of Felony Murder). It's the same as a manslaughter, which is a felony crime.). If the Driver is turning left, it depends on the signalling. Dedicated turn cycles (Green Arrow Left, Red Light Straight) than the Pedestrian must wait until it is Green Light Straight to enter the intersection. If left turns are unsignaled, or are permitted when Green Light Straight, then the driver must yeild to oncoming traffic and pedestrians crossing with the light, so the ped he missed would be off the hook.
Similarly, unless sinage has different rules, Right hand turns are always after yeilding to pedestrians, even on green. In all scenarios, traffic in the process of clearing an intersection has the right of way if the light changes from Yellow to Red and new Green Light traffic may not proceed until the intersection is cleared.
In scenario two, this would likely be a no fault to the driver no matter what, as the person who was hit was also jaywalking. THe specifics of the incident may cause the surviving ped to have some trouble but this is not open and shut as to whether a driver is at fault. He would hit a ped no matter what he did.
In scenario 3, assuming it was a proven suicide attempt, the suicidal pedestrian would likely be liable for manslaughter.