Marrying a Shia

Q: I am a sunni girl, Sayyed by cast and got a proposal from a Khoja Shia non Sayyed boy.

My question is, is it ok to get married into a Shia family? If so, what is the right way to do nikaah? Should it be done both ways? 

Playing games that contain blasphemy

Q: While playing video games, if the character we are playing utters or does something blasphemous, do we lose our imaan.

1. Does blasphemous talk involve Christians cursing too?

2. What is the definition of blasphemy?

3. What if while playing a game, I accidentally chose a character whose dialogue is known to have blasphemy in it. But, during the entire duration of the play, that character did not say any such thing. However, since I know that the character says such things in other instances of the game (even though those instances did not come when I was playing), I am now worried about my imaan.

Would my imaan be in danger because of this and will I have to redo my nikah?