Take a look at this thread
http://www.pprune.org/professional-p...d-nauseam.html
That should answer a lot of your questions.
However, the basic answers to your questions are:
1. Yes it's cheaper, yes modular guys have got jobs with major airlines, and yes you end up with exactly the same licence - fATPL.
2 & 3. It depends on a lot on the airline. For example BA won't take low hour modular guys, whereas others will.
4. Again, some airlines will prefer some schools to others, and of course your individual training record will be an important part of any job prospects.
Unfortunately there isn't a simple yes/no answer to a lot of those questions.