If I was creating a half-fiend noble drow (or any other inherited template / character race combination), would the ability adjustments from the inherited template replace those from the race, or stack with them?
The wording isn't as clear as in some of the other templates. However, if you compare the Half-Fiend Minotaur to the Minotaur, you should easily see that it's added +4 to each of the physical stats of the existing creature and +2 to each of its existing mental stats.