Dear Ali,
It seems you really planing for something big, about your queries I am giving you the best answers upon my Experience and Knowledge.
1-On an average 80% workers dose not takes more than a month to learn and get used to with a little complex job, but you have to find the capable,willing to type workers and have to have good trainers.
2-Gender issue is almost as same as Pakistan, just ensure a good environment to avoid unnecessary problems.
3- Usually worker category employees stays at least 2-3 years and more depending on working environment and offering by other companies.
4-For workers, minimum wage is BDT 3000 excluding over time.
5- Kitchen Expense and utilities depends on food habit and life style for mid level 8,000-10,000 and for pos level 10,000-25,000.
6-According to traffic conditions of Dhaka it will take 1.30-2.00 hours to travel.
7-No special Do or Dont peoples are cooperative here, just be well mannered.
8-Two Bed room Flat in Gulshan/Banani 22,000-35,000 and in Dhanmondi/Eskaton 18,000-30,000. Both areas are pos and This rent is for non furnished flat.
9-Usually most of the foreigners lives in Baridhara and Gulshan. I also know few Pakistani communities they lives in Dhanmondi.
I hope these information will help you, if you have any other queries or you want any cooperation, feel free to mail or call me.