Dear sir,
In the even of you dying intestate (without a will), your property would be shared in three parts between your mother, wife and kid (1/3rd each). If you happen to have another child, the share would further be divided into 1/4 each.
Therefore:
1. Yes, your wife and kid will get 1/3rd share each.
2. Your mother will get 1/3rd share. Your, father will not get a share.
3. No. Your sister will not get a share.
However, please be informed that, if you make a valid will, the property will devolve according to the will, and you can choose to give it to anyone you wish to.
Hope this answer helps.
Best wishes.