1) Wife send 3 Notice to husband address but husband not staying that address .. what will Happened ?
Opinion: The petitioners has to publish the notice in the leading newspaper and request for ex-parte after non appearance of husband.
2) After 3 notices (husband not received) court can pass ex part Divorce to wife.
Opinion: as stated above
3) Basically i heard with out any procedure after 4 years husband wife staying separately no any relation they both of automatically divorcee
Opinion: Nothing Like that..
For permanent separation and to re-marry you have to legally divorce through court.
And nothing goes automatically even non consummation goes for 20 years. Still they will called as husband and wife until and unless either of them not goes for filing divorce on said ground.
4) with out any divorce procedure after 4-5 years both of go for second marriage and this second marriage is void or valid.
Opinion: Void ab initio as well as it will counter for Bigamy if it is proved but chances are less as marriage is void.For Bigamy a valid marriage is needed with evidences.
5) After 7 Years marriage period still wife can case filed for 498 Case.
Opinion: Yes she can file 498A even she is at her oldest age. There is no barred for filing any cases in India. It only needs a greedy Lawyer + unscrupulous thought.
But IPC 304B can't be entertained after crossing 7 years of marriage.