Hi,
Yeah if you fill in the common form for all 4 councils and pay your €50 to whoever you end up posting the form too your €50 covers for all 3 or 4 councils....
For the long-form version (for all 4 councils) you need to give all details of salary, savings etc upfront as far as I remember....
The more savings you have the better mortgage you'll get and the council dont care about any of that when you first apply anyway. As long as you're not earning over 55K you're grand.....you also have to have evidence of being able to save approx €750 a month or something...again I can't really remember as it was about 2 years ago when I applied initially,
Hope some of this helps