Paying for one's studies with haraam money

Q: My questions are regarding haram earnings and investing it in education. I have learnt that investing haram money in a halal business is haram, and any remuneration is impermissible. This is what I understand.

1. If someone invests haram money in education by purchasing a course(s) that are permissible to study like language, science etc. and then they go on to study a degree also bought with haram earnings, will the knowledge that they acquire be permissible for them to use?

2. What is the status of the certificates and/or degree gained? Are these things haram for one who acquired them to keep or show employers?

3. And if he goes onto use this knowledge in a profession like medicine, teaching, engineering etc. will his earnings be haram? For example, he studies GCSE's, A-Levels, then goes onto study a degree in physics and then becomes a physics teacher after qualifying; will his earnings be haram after he spent haram earnings on all his previous courses?

Wazifa for protection

Q: My son is 4 years old. He says that he is able to see insects who are opening their mouths and coming near to him. He gets very scared before sleeping. Before he goes to bed I read the daily sleeping duas for him but I want to know why he sees these insects.

Can the one appointed to purchase make a profit?

Q: I need Shar'ee guidance regarding a certain trading transaction:

My relative asked me to buy a washing machine for him. The washing machine cost Rs.3000 for example.

1. Can I inform my relative that the machine cost Rs.5,000? He does not know that I will charge him extra. 

2. Can I first inform my relative that I started selling washing machines and then charge him Rs.5,000?

Getting married under the age of 18

Q: In Islam, is it halaal to get married under 18 but by Law its illegal to get married under 18?

My question is: Can I do nikah but not get married by Law (I'm under 18 and the girl is under 18 too and we are in Europe... In my country like most of the countries its illegal to get married under 18)

Ma Sha Allah im 17 and she is 16 which means we have to wait 2 years... We both are muslims Ma Sha Allah, and she has a "wali" and everything else. Alhamdulilah its okay but that is the one and only problem.

Unmarried woman taking an oath that if she does something then her nikaah will break

Q:

1. If before giving the marriage consent in front of witnesses a girl takes an oath that if she does a certain thing her nikaah is invalid but she breaks the above oath when she is married ...is her nikaah valid?

2. If after giving the marriage consent in front of witnesses a girl takes an oath that if she does a certain thing her nikaah is invalid but she breaks the above oath when she is married ...is her nikaah valid?