Looking at the messages in the discord, he seems to have figured it out already. The rules of the category are mentioned in the original post and state that you must either play through Prologue (and show it) or load into an autosave created after Prologue. What you're suggesting would not work anyways since it'll exit the mission replay once the mission has been finished. After you finish Franklin and Lamar, you still have around 10 stunt jumps left to do.
Yes, all targeting modes are allowed in the speedrun.
Most people on console use the Frameperfect app on their phone to time their splits.
As for the suggested routes on complications, none of them are faster. Even though there are less turns, the extra distance we have to drive would cost too much time. Even while hitting all my brake boosts I couldn't get near my normal time. The route on Franklin & Lamar is quite interesting. The route itself is indeed faster and the scripted truck is easily avoidable. The only problem is that I actually go too fast, causing me to lose Lamar. I tried slowing down at different points. While this helped, I would lose too much time doing this. On my best attempt I was four seconds slower than the drive on the IL Record. Unfortunately I'd say that the route wouldn't save time.