Sounds to me like you have a lot of questions. I think you would be better off taking it to a mechanic or attending a trade school so you can learn to work on cars. Brakes are nothiong to be fooling with, however a good shop manual should help you through your dilema. Go to wherever you bought your brakes and ask for a Haynes manual....
The 1967 Ford Mustang had hydraulic brakes
Not unless they were added by someone as an aftermarket accessory. Pretty much, only the F700 and above were made available with air brakes.
My 1971 Ford Mustang , fastback , with 351 Cleveland , 4 barrel , had drum brakes on the front
No.
how to change front and rear brakes on a 2003 ford mustang V-6
Depends on how old and how the older one was equipped
No, it will not.
The 1987 Ford Mustang came with a T-5 five-speed manual or optional automatic transmission.
Should drop right in...same engine.
that depends greatly on what is wrong with them.
+/- 5 quarts
5x4.25 like the mustang