Joining the army to become a mercenary

Q: I am 18 years old and will be completing my schooling this year. I am considering joining the army after I matriculate. Initially, after my training is complete, I will serve a certain amount of time in the army and may even be called upon to fight for the country (as is happening currently, where South Africa is fighting in certain other African countries).

My idea is that after some time, when I have sufficient training and experience, I will leave the army and become a mercenary (a soldier for hire). There is a great demand for mercenaries, especially in dangerous countries such as Iraq and other war-ridden countries like the African countries suffering from war lords, etc, and this profession is extremely lucrative.

Is this profession permissible in Islam?

Women's dressing

Q: I live in Saudi Arabia, and I just got engaged to my cousin who lives in USA. I'm aware of the cultural differences between the two countries. I'm worried about how my cousin should wear clothes. I didn't ask her to wear abaya because she said that girls in USA don't have to wear abaya and it's not necessary in order not to get men's attention, like in Saudi.

She also works in big well known company in an office environment with men and women together. I would like to know what Islam says about wearing jeans (not tight), makeup (little bit) and high heels shoes? And is it ok to work with men in an office environment, and is it ok to ride in a car with a male colleague?

2. How should Muslim men and women conduct with their brothers/sisters in law? Is it ok to talk or sit together with them in a family gathering? Is it ok to travel with them together with one's husband?

3. Is it ok to shake the hand of a non-mahram?