fabbe92
You will benefit by far from having a good solid education with good grades and I would not sacrifice those grades for flying. At the moment all you want to do is achieve a flying position with a quality company as soon as you can. That is understandable, nothing wrong with ambition at an early stage, but, after a couple of years you might change your mind, you might find you're not cut out for an airline career after all. You need options, and that means good school grades. Also, if you do go into aviation, those grades will help with developing your career later on.
All of the FTOs that you mention are good outfits and they regularly supply the leading airlines with newly qualified First Officers, your choice is going to be made nearer the time, when you are ready. Keep an eye on what airlines require. Write to them, find out the sort of people they recruit.