Spousal rights to property

1. What about when wife gets 50% of the husband's property upon divorce, won't same law's would apply in my case if I buy a new property before divorce?

no such thing applies on property of wife owned by her. 

  2. What about when estranged wife's does not leave husband's house until settlement takes place, won't same law's would apply in my case?

it is not like that, you can leave but yes if you purchased a house it will effect your maintenanace and Almony. your husband has then right to refuse or pay minimum alimony .

  3. Can my estranged husband allege that the property is purchased from marital income?

yes he can, he will and he has every right to raise any attack,