From my limited knowledge, but what I was involved with while an elder..................
A dub I personally know had this dilemma about 20 years ago. Dub had a very good job working at a nuclear laboratory. Problem was......once said person became a dub and learned about not working as a defense contractor, dub had a problem. Dubs paycheck came directly from the U.S. Navy. Other people worked with the same lab. Some got paid by a contractor, others by the Navy. This dub became very concerned about this situation. After consulting Brooklyn, the dub was ordered lovingly told to find another job within a specified time. From a very nice position and a good paycheck, this poor JW has been cleaning offices ever since. She is a very happy camper to this day thinking that Jehovah will soon take care of everything.
I will admit it though. This sister is a very humble and sincere person. One of the few I knew who could be trusted.
As long as your paycheck doesn't come from the U.S Navy, Army, etc. it is ok. Most consultants receive pay from another party connected with the Dept. of Defense or other govt. entities.
So according to Brooklyn, it is ok to do work for these entities as long as you are not directly paid by them.
HappyDad