i went 205 to 158 in 3 weeks, then 158 to 152 in 6 weeks.
yes it's possible. you'll need lots of race pace work
I doubt you can cut that much time even if you had not been injured. It's just a lot to cut off. If you are a freshman with little experience it could happen. If you are a senior it is not happening.
I wouldn't spend any time in a base phase. You need to be doing hard aerobic workouts (5k pace repeats) and anaerobic workouts (mile-800) pace repeats each week .