I think it is safe to say that the battle for starting QB next season is between Jake Heaps, Montell Cozart, and TJ Millweard.
Here are there college stats for last season:
Heaps: 49%, 1414 pass yards, -162 rush yards, 8 pass td, 1 rush td 10 int
Cozart: 37%, 227 pass yards, 214 rush yards, 0 pass td, 1 rush td, 2 int
Millweard: NA
Now these are high school senior stats just we have some numbers we can use when comparing Heaps and Cozart to Millweard:
Heaps: 61%, 9195 pass yards, 153 rush yards, 45 pass td, 9 rush td, 7 int (Sammamish, WA)
Cozart: No official high school stats (Overland Park, KS)
Millweard: 67%, 2374 pass yards, -52 rush yards, 22 pass td, 0 rush td, 11 int (Fort Worth TX)
The numbers all seem to point toward Heaps, but Cozart beat him out for the #1 QB spot on the depth chart by the end of last year and Millweard has been reported to have been the second best QB on UCLA's team when he was there.