are all the people in the sudan embassy at washington are diplomat?

Answer 1

No, not all staff at any embassy or foreign mission are considered diplomats. Even all those that carry diplomatic passports and have a degree of diplomatic immunity are not necessarily considered diplomats, though they may be ranking government officials.

The following US Department of State site is a good example of mission staffing:

http://www.state.gov/m/ds/immunities/c9127.htm

Answer 2

I wouldn't believe so. They would have office staff, etc. that generally would not qualify as a diplomat. Few people at an embassy are what we call diplomats. They may travel on diplomatic passports, but that is just for identification of them and their work, makes it easier in country. However, I'm sure that every country has a different outlook on it, too.

Answer 3

one cannot compare a third world state like sudan with american diplomats and staffing sudan probably has a whole bunch of people paid to study in the states or other countries as well as whole bunch of people to canevass for foreign help rather than investors
a few years back studying in france i was flabbergasted to learn my mauritanian neighbour whose father was a counsellor to the head of state had a dimplomatic passport while being legally employed at his embassy while simply studying at a nice university
that is the type of staff those third world countries have at their embassies and where tax payer money goes when you live in a western country