Nikaah & Marriage Issues

Condition for the validity of nikaah

Q: In my area the Shariah is not applied to its extent. My question is regarding marriage. There are many so called Muslims getting married according to the customs of this area which is not in compliance wih Shariah. People roam freely to choose and meet there life partners instead of the Shariah compliant way. Will these marriages be cosidered as Legal according Shariah?

Polygamy

Q: 

  1. Are second, third, fourth marriages a sunnah?
  2. Is polygamy encouraged in Islam (emphasized sunnah) or is it something permissible?

Marrying the stepmother's daughter

Q: Please first understand the whole story then give me an answer. My sister is married to my uncle (father's brother’s brother in-law). Before my uncle died my uncle and my father announced the engagement of his daughter with me, after few days my uncle died. As few years have passed, my grandfather decided that my father will marry my aunt and they got married. Now around 12 years have passed and my aunt is forcing me to get married to her daughter and my father has also agreed. Can I marry my step sister which is not from my father?

Paper marriage

Q: My question is can I do marriage just in papers not actually with proper intentions nor physically. Also the female knows its just for papers not actual marriage. Its just to gain visa. I consulted with a lot of people most of them said if you are not betraying the person its fine Islam allows to make secure your future and for a better life. The example in my mind is about our prophet Ibrahim (Alayhis Salaam). He said his wife is his sister. Its just to obtain UK registrar office certificate and to put it in file but to make a strong case you have to do nikaah as well. This all is in papers. Only I and her know about this that this is just for visa.