Not legally
No. You must be 18 to purchase a rifle of shotgun. yes at 16 in Indiana you can buy a shot gun or rifle from a gun store without a permit I live in Indiana so I should know.
18, pass NCIS, have money
None. A gun in the home, or anywhere else for that matter, will not shoot you. If you are asking what are the odds of being shot by someone with a gun in your home, that's another question. You will have to be specific in what you are looking for. Is there a gun in the home already? Is it loaded or empty? Is it secured or not secured? Are you asking about being shot accidentally or during a crime in the home?
I can, and do. However, it will depend on the law where YOU are- and you did not tell us where that is.
Take the gun to a licensed seller, and get the address for a licensed seller in Indiana, have them ship the gun to Indiana.
You will need to contact a lawyer. To many variations in local and state laws for a cookie cutter answer.
You will need to get a lawyer and provide ALL THE DETAILS of your crime, trial, conviction, sentence to get an answer.
No
To hear the gun shot at the start of the race
Yes.
Leave the gun at home and walk away. No reason to shoot a snake. A revolver with shot loads.