look in the outfit section of your journal and it will tell you what you need to do
Go onto the outfit menu and you will find out what you must do to unlock that outfit.
First you have to beat the game then you go to El Matadero and see the guy at the barn then it will guide you from there
No.
there is not one sorry
Yes.
Go to the outfits menu in the pause menu and you should see what you need to do in order to unlock that outfit.
You have to find the 5 Treasure hunters and kill them, Then You get the outfit, Then you go on a mission with them and You go into Mexico
there is no code you have 2 unlock it yourself :)
You cannot get a gang in Red Dead Redemption, but you can be part of a gang by accepting a wanted poster, then wear the outfit of the gang, then they won't attack you.
If you don't have it already, you can simply purchase it from the PlayStation store, it allows your fame to increase at twice the rate.
You can not physically join the military in the game. The closest thing to it is the main quest line where you help Reyes overtake the Mexican Government. There are also outfits you can unlock like "The U.S Marshall Outfit" and "The American Army Outfit" But they do not put you in the military.
Yes, you just need to unlock it.