My opinion on your queries are as under
Can my inlaws put false case on me and how strong is 'Protection order'?
Opinion: it may be possible, protection order may be granted by magistrate court if you file domestic violence case against them.
Can it be challenged? My mother in laws challenges me that if go back, she will break glass doors and windows and utensils and put blame on me and ask policemen to arrest me. What can i do for my safety?
Opinion: file a domestic violence case and try to get protection order, right to residence order, maintenance, child custody if any and compensation as per section 18,19,20,21&22 of protection of women from domestic violence act 2005.
My husband is also standing with them. I do not want to stay at my parents home more. I also have a one year old kid. Can these people sell house and throw me and my son out of their house again if i return there?
Opinion: the magistrate court have power to restrain them to sell the matrimonial home without due process of law. Or the court may grant you to reside in rented accommodation and the rent will be paid by your husband.