1) has your wife challenged the talaq given by you ?was divorce preceded by attempts at reconciliation ?
2) as far as child custody is concerned after age of 7 custody of son is with father . you should draw attention of court to said fact that your wife cannot be given custody of children as per your personal law .
3) welfare of children is paramount consideration and their wishes must be taken into account
4) you have to go by your lawyer advice whether it is necessary to examine more witnesses . it would depend upon allegations made in DV complaint , evidence on record till date
5) if your ex wife is not working court will award her maintenance and also alternative accommodation