Re: Business in Pakistan ...
^^I hope that overseas Pakistani has either worked or have done business with Pakistani retailers before. if he is thinking to hire ground staff and make them work or observe them remotely is extremely difficult.
The best option would be to find at least 2-3 suppliers currently dealing with such retailers, sign up non-exclusivity agreement to supply the products but keep the quality Assurance in your own hand. Make good relations with the retailers, if your local partner messes up, you can go direct.
the Overseas Pakistani can form his company simultaneously while signing up partners. You need to learn the tricks of the trade in Pakistan first.
As per taxation/licenses, being on the ground would really help compare to reading it online. As i said earlier, you need a good corporate lawyer & an Accountant.