visiting Shanghai 7 -12 march. Advise on weather, clothing and muslim food please.

it is so early to tell the exact temperature at that time in such an early time.
According to the past records, the average temperature is around 8 to 15C during that time. So think the T-shirts and coat are necessary.
The muslim food may not be easy to find in that city, but I know one in the Bailian Shimao International Plaza and the restaurant name is called Yeli Xiali Restaurant.

Muslim restaurants quite popular in the city, easy to find due to the "green" sign often showing a Mosque. Many are very small, simple , economic and serving home made foods, with a menu hanging on the walls showing photos of the dishes. Enjoy !