Honestly I don't know how to respond to these posts. It's so dependent on outside factors that we don't know about, that it is quite impossible to say for sure whether its possible or not.
Personally, I was a 4:44 1600 and 10:18 3200 Sophomore, and then a 4:28 and 9:39 junior. So the times you are saying are achievable for sure
However, it is not likely. At least I don't think that it is very likely. This improvement isn't out of the question, but it also at the same time is not very common. My mileage between sophomore and junior year varied from 45-75, with my two peak weeks at 75 during track junior year. However, my senior year my mileage never went above 52 and I still had marked improvements(4:19 1600 and 9:15 3200). So I'm not sure how much extra mileage helps.
Honestly just go for it, but stop stressing out on the plan or if its possible or not. That type of thinking won't really help.