Groceries: 4 people cost me an average of 5-7000 aed / months
Gas: None, paid by the company if company accommodation provided. If you chose the house allowance....
School: It depends of the school. EK participates widely to the cost, but the school fees are so expensive, it cost me an average of 1000 aed / month, salary deduction
Internet/phone: basic elife at 299 aed/month, +++ depends of your needs
Skype: needs a VPN
Dressing: depends of you and your family, I dress for a cheap price, but cheap quality, no choices!
Homemade: ? do you mean maid? = 1000 to 3000+/month
Car insurance: depends of your car... an average 4x4 = 3-5000 aed/year
Mobile phone: basic prepaid plan at 100 aed, no internet... an average plan is around 400 aed/month
+ UAE ID (370/soul) + Salik + Car renewal + multiple knowledge fees at 10aed ;-)
+ Does your wife want to work?
+ what are your kids' activities, this is the most costly part of life here, any single activity is! Soccer, 15-3000 aed /term, Swim - same, Music activities = 1000/month, private tuition is very costly too!!!
Seriously, the cost of life has increased a lot... Salaries didn't... I am not saving anymore money...
I would suggest you to go online and compare the price of your own groceries (Carrefour.ae is a good start)
Good luck!