I am planning my nikah but the bride is not a Muslim. She is Christian but not practising. Does this affect the validity of the nikah? Does she has to be convert in order for the nikah to happen?

Also she is from another country and all her family is there. Her parents have given their consent but none of her family will be able to assist the nikah. Could be the Imam be the wali in the ceremony? Will that affect anything? do their parents has to do something?

Also she would like to do a civil ceremony later at her home country with her family, can be the legal part done later?

I hope you can answer all my questions.

Thank you.