I'd say forget developing into an ENFJ. If it were me, and it probably will be, I'll handle it by developing study habits that fit well with the INFP. Instead of trying to change myself, or risk changing myself, I would change my schedule to work with myself.
As for writing, you worded the post pretty well. You definitely have good grammar, and at least know how to get your ideas across. I'd take up poetry. Well, not take up poetry. Just try it some, in your spare time. Think of it as writing song lyrics, if you're musical.
last question: Yes.