Questions about the DLC speedrun trophies..

[rockstarjazz]

i hope to do the trophy for donut drake and the overall time limit together. my questions about this are..
1. when completing a chapter it says 'segment complete' with option to start next chapter. if i choose to quit at the end of the chapter to take a break and wishing to turn off my ps4 and go somewhere, will that break the overall speedrun trophy and the donut drake trophy? i notice when i quit chapter 3 upon completing it, and went back to the many, at the top instead of continuing chapter it said 'play' and i selected this and it took me to the start again, so how to i resume my speedrun, can i just simply select the next chapter? wouldnt this break the 'continuous' speedrun?
2. for the total time speedrun trophy, is it possible to do the whole thing, and if i am over, to select specific chapters to cut the overall time down to get the trophy if the total time falls within limit?
3. what fights can i skip in the speedrun? it wasnt clear on the roadmap.
4. how forgiving are the time limits? must you be exact and spot on in everything you do that even the wrong turn or taking too long in shootouts would harm my chances of getting the speedrun trophy?
5. if i restart a checkpoint would that affect getting both trophies too?
thanks