No, there is no such provision or clause stating the borrowing more than 80% for expats of the property price. But, yes you can avail finance on land department and real estate charges as a part of mortgage.
Yes, Banks acquire professional services of Al Etihad Credit Bureau that collects the data of different kinds of loans, credit card facilities, and credit score. Which helps banks to have better idea on the credit history of person. But bank seeks approval/consent from person to go through such a checks
UAE is one of the best places to invest, well connected globally, Even the person who is not a resident in UAE can purchase property and also have facility to avail mortgage from banks in UAE. This is the beauty of this place. Plus your investments are totally secure.
Mortgage broker plays a vital role to bring best of the deals from the market for you, as they have access to all mortgage deals in the market from different banks, so they can bring the best which suites according to your profile.