No, there is no spell to make your chest grow. Your chest grows naturally when it is ready, there is nothing that you can do to speed-up the process, certainly not magic.
Fire!
If the hair came from the same person, the results will be similar. Chest hair doesn't grow as quickly as head hair and falls out sooner so the time period would have to be adjusted.
There is no such thing as "chest hormones"
your naturally grow hair on your chest if your a male and for a female i dont know
sometimes
Well my 2nd cousin had full chest hair by the time he was 13.
None; chest hair and body hair are determined by genetics and age and by nothing else. If the adult men in your family have chest hair, then you probably will get some too--though in many men chest hair doesn't grow in, or grow in fully, until their 30s.
No it gets it ripped and more shaped.
Not particularly, unless on steroids.
Yes, any body hair you wax will eventually grow back.
Yes, it will grow back thicker and darker. But shaving your chest itches very badly.