If you want to do an integrated course, why would you want to do modular ATPL exams? An integrated course includes the ATPL study and exams.
Modular schools won't let you enrol for distance-learning ATPLs until you have a PPL. You could buy Oxford's notes, for example, and begin studying in your own time, though when you begin with a school you'll end up buying the notes all over again as part of the course cost.
Bascially, if you're going integrated, you don't have to do *anything* before you show up on day 1. If you're going modular, you must get your PPL before you can begin ATPL studies. And yes, it is viable to do the studies alongside a job - this is what most modular students are doing.