My opinion:
1. I dont know much about Mannai Group, what i know is they are a reputed group and have lot of businesses in Qatar.
2. Expenses for a family (average)
2 BHK FF Accommodation - 4,500 to 7,000 K per month.
School - QAR. 12,000 to 18,000 per child per year in Indian Schools
rest all are mostly same as other GCC.