Masaail pertaining to the Wali and Compatibility between spouses

Q: I am computer science graduate and working in a multinational in my homeland. Throughout my life I have struggled hard to get my achievements because I am a disabled person. My left limb is artificial but Alhamdulillah I have always overcomed my disability in my life. Now I am in a very good position to support myself as well as my family. After my disability I have moved and studied with others and I also do the same jobs like other normal people. My personal analysis is that I can do Nikah which is declared a part of faith in Islam. My parents are also emphasizing upon me to marry now at the age of 29 years. I love my religion and try to follow all sunnahs Alhamdulillah. The questions I like to know is that   I know a lady not in my family but relative to my elder brother's wife whose husband died in an air crash in Pakistan. This widow lady is the mother of two and also taking care of her husbands mentally disabled sister. I have intention to marry this lady as I have met her late husband once in life and due to the character Islamic personality of her late husband I wish and  feel  to provide the love & care  to her and her children in an Islamic manner. My wishes and intentions are all within the limits of my religion but my disability is the obstacle in my  powerful ambitions. I have to take this important decision in my life so everything I wish to do is according to the will of Allah. I have few questions to ask you.

Q: I loved a girl. We both were in love for sometime and family come to know about us. My family accepted our relationship and my mom asked there daughter for the marriage for which they refused. We are not in touch after that. After one year they sent us the proposal that they want to marry this girl to me. But I come to know some strange facts that she also had a relationship with her uncles and she also has boy friends. I didn't know she was a cheat. I have all the proof that she used to talk with her cousin brother and uncles over the phone. Please advice me. Is it permissible to marry this kind of girl? 

Q: Is it necessary for the wali (father or any other guardian in the absence of the father) of a baaligh girl to seek her permission before getting her married?

Q: I have been offered a proposal of marriage from an Indian sister. Her parents are denying her the nikah based solely because I am white. They will only allow her to marry an Indian man. She is 21 years old and a Hanafi. May I request the official ruling(s) in regards to this issue.

Q: Is marring one's mothers cousin allowed in Islam? I am a IT Employee working in an MNC. I have a question and seeking your guidance under the light of the Hadith. There is a girl in my family and she is my mothers cousin sister. I stay in a different city as I have job there. I some times chat with her over the internet. Just a very normal chat like "How are you & every one at home?" "What's going on? This and that." Our family know that we chat. Once I asked her about her marriage proposals. She said that many people come to see but no one is selecting her. Every one is taking out some reason or the other for rejection. I went to an IT conference. There was a topic "Why are Girls not getting married?” The reasons and the worries of the parents were explained. We were encouraged to move Forward and do some thing for the sake of Allah. Allah will reward you for what you do. I decided to marry her and wanted to tell my parents, but before that I wanted to ask the girl. She took some time and she also agreed. So I told to my parents and my parents were ok with it. She also told the same to her parents. This has became a very big issue now because of which there are disputes in my family. I want to know if what I did was correct or wrong and what should I do now?

Q: I intend marrying a girl with diabetes. She is Deeni inclined. What is your advise regarding this matter?