As someone who is waiting to start the basic training in September, my two cents is this in regards to stage 2 preparation and other things...
There is nothing to do to prepare for the FEAST and DART tests. If you buy some sort of product that gives you some tasks to complete, they may be different to what you face in the actual tests and you'll hesitate and screw up. If you think about it too much going into it, you'll screw up. They want people who can naturally pass it, and quite frankly I wouldn't want to do the course if I couldn't have naturally passed it considering how difficult they are reassuring me the course will be. If you have the natural skills you'll be fine, and I imagine a lot of people would only have applied if they thought they could do the job on some level.
Also, people on here seem to be worrying about the size of the groups taking stage 2. Don't worry, they do many groups of stage 2 interviews and bring them out all around the year so even if you haven't had one, don't panic. Just resume you're day to day life, check the e-mail for any new open dates and stop worrying about it.
I had to wait 2 years altogether for my application from submitting the initial forms to being told I had passed stage 3. A year and a half of that was between passing stage 2 and awaiting stage 3. In that time I studied 2 levels of the UKs AAT accountancy qualification just in case things didn't work out. Luckily for me they did work out and I couldn't be happier, but please don't put all stock into this or it will hurt that much more if things don't go the way you expect.
As I said, just my opinion and thoughts, hope some of you may find this reassuring or useful perhaps. Good luck to all of you and extra congratulations to the people joining me (CJCon and FlyingMackem) on September 1st!!! (pending medical of course, terrified about it haha).