1. Address the reasons in your personal statement why your GPA was not so hot frehman year and why it dropped off in your Junior year. Addressing this is going to be really important for you. Specifically mention how you grew from the experience. If you don't, schools could see this as a fool me once shame on you, fool me twice shame on me scenario.
2. I would not mention the reason you took the DAT twice was because you didn't practice math/eng/pat. I would think the admissions committees would be paying more attention to your QR section than most applicants due to your performance in math courses in undergrad.
3. I agree, an 18 on PAT is pretty good w/o practicing.
4. Bear down and crush the DAT, it will help deflect attention off your GPA.
Best of luck! This thing is an endurance race! 🙂