Hello there. My advice is that PPE is competitive, so don't assume anything. Your academic record and predicted grades are indeed very good, but that will be the case for all who apply. You'll need to score well in the TSA as well in order to be in the running for an interview. It's a tough business applying for PPE!
In picking a college, I wouldn't try playing the numbers game, as it just doesn't work. All PPE applicants are assessed as a cohort. All those whose applications score lowest will be rejected and there will be a redistribution (with many being reallocated to other colleges) of the rest to ensure that the spread of applicants is equal, both in number and ability across the colleges. That said, you stand more chance of getting into your college of choice if you apply there. Come to the open days in July, if you want to make a truly informed choice of college; there's no better people to ask than current students.
You can read more on the TSA here:
http://www.admissionstestingservice.org/for-test-takers/thinking-skills-assessment/tsa-oxford/preparing-for-tsa-oxford/ The only thing you can do really is to practice past papers. This will, at the very least, enable you to plan your time accordingly, which is where many slip up.
We can't speculate or discuss questions. Tutors' styles will differ between colleges, so I would simply just expect the unexpected. If you're bright enough, you'll cope!
Extra curricular activity isn't really looked at that closely. Tutors would expect to see something on the UCAS form, but I'd only devote a few sentences to it and only if it's relevant.
I hope this is helpful, but do feel free to email should you wish to continue this conversation:
[email protected]Libby Charlton (Admissions Officer)