Working in a mixed environment

Q: I have been offered a job as a mail sorter with a postal company. I will simply order and arrange post, letter and parcels and check the postage has been paid. But some women work there although they work in a different section so I would not have to look of mix with them at all, they also play music in the background. Is this a halaal job? Please note that I live in the UK and most jobs here contain some haram things like alcohol, haram foods, haram clothes, gambling, riba, free mixing, Christmas, easter gifts cards and presents. I am very poor so I can't do hijrah to a Muslim country and my mother is forcing me to do this job as we are in need.

Sunnats of nikaah

Q:

1) Is want to find out the correct procedure of a nikaah/waleemah.

2) What is the sunnat method, what are the sunnats of a nikaah.

3) After the nikaah is performed, how does the groom meet the bride? Is it done in privacy or infront of the family?

4) Is there a salaah that the bride and groom read together? Is there any such thing as giving the groom milkshake/sarbat?

5) Any advices for the bride and groom?

Names

Q: Are the following Sahaabah and what do these names mean? Al-Mugheerah, Al-Ahnaf, Al-Aqra'? Also Al-Lajlaaj and Al-Irbaad?

Removing impurity from the door

Q: If there is visible impurity from along time ago and was never cleaned what should I do? And how would I clean it since its on a closet door because I can't pour water on the doors. Also if I use a soaking wet tissue, if the water while wiping falls on the carpet will the carpet become napaak? I avoid those areas of impurities so after I do wudo and close the door where the impurity isn't there will I become napak? I have read namaz many times before after doing so, did they not count?

Becoming a shia

Q: I have committed zina twice. I repented once after the first time and made the mistake a second time. I'm not sure if my repentance will be accepted by Allah Ta'ala. After I committed the crimes I became a Shia Muslim. Have I taken the wrong path? I really need help.

Wearing white gold and platinum

Q: I will be getting married soon Insha Allah. I know that men are only allowed to wear silver and women are allowed to wear gold and silver. However what I wish to ask is that is it permissible for men and women to wear white gold? Is the law of white gold any different from the law of normal gold? Could you also explain whether men and women are allowed to wear platinum?