Indemnity clause should be added in sale deed to indemnify you in event of third party claims are made 

2) spouse and children can be witness to  sale  deed

3) family tree should be enclosed to sale deed and NOC of spouse and children  

If the registered sale deed is on her name and if is in possession of the chain or link documents to establish the clear and marketable title,  after obtaining a legal opinion from local lawyer you may proceed with the proposed purchase of the property. 

There is no necessity for her children or husband to sign the sale deed neither there's any necessity to obtain legal heirship certificate of her. 

1. In the sale deed let seller's source of money by which she bought the property be mentioned so that it will be known as to whether it's her self acquired property or benami property of someone else bought in her name.

2.  If the seller is selling her self acquired property there's no need to have the signatures of her spouse and children. However if her spouse and children are ready to affix their signatures it can be welcomed.

3.  If you could get family tree signed by Tahsildar and NOC for sale from her husband and children it's well and good. For a person owning self acquired property there's no need to get NOC from spouse and children for  selling the self acquired property.

1. Check the antecedents of the vendor.
2. Title of the property: - Office of Sub-Registrar will have records history transactions on the If the land is an agriculture land then adangal/pahani/khata of that land or/and Pattadar Passbook and Title Deed can be verified.
3. Mode of acquisition of property by vendor: verify the following documents.

   1. If the property is acquired  by gift, registered gift deed.
   2. If the property is acquired  by partition, partition 
   3. If the property is acquired  by grant from State Government, check if lock in period against transfer of property is completed.

4. Physical verification of property: carry out a personal inspection of property on holiday when all neighboring property owners will be available at the Coordinate dimensions, boundaries and extent of property is particulars given in title deed.
5. Original documents: Seller should have and produce title deed and all link deed in originals. That will rule out mortgage of property.
6. Obtain encumbrance from the office of Sub-Registrar.
7. Property tax and payment of amenities: verify whether all property taxes and charges against amenities like water and electricity are paid.
8. Take no objection to sale of property by all legal heirs.

You need to get the entire sale deed drafted by a lawyer. Such questions can’t be answered in consultation. Signature of all legal heirs needed 

Engage a competent lawyer and ask him/her to verify all the documents and render his/her opinion in writing. As the vendor is a homemaker, it has to be verified if the property was acquired by her from out of her own savings. Otherwise, the husband may claim later that it was purchased from out of his funds but registered in her name. The husband or the major children signing as witnesses shall not strengthen the vendor's title legally, as witnesses are not legally responsible for the contents of the sale deed.

Dear client, a women can sell can sell her property to any one without the husband's consent. The husband or legal heirs cannot have right over her land if she wanted to sell. 

In sale deed there will be a clause that after transferring the land the owner or any legal heirs cannot cliam right over that said land.

You can add a clause like this, for example: Hereafter you and your heirs have to peacefully hold, use and enjoy the same as your own chattel and property without any hindrance, interruption, claim or demand by me or any other person whomsoever. The same shall be enjoyed by you and your heirs and either myself or my heirs will not raise any dispute in respect of the schedule property. 

Other way also you can ask the legal heirs and husband to sign as witnesses and also can take an signed NOC declaring that there will be no objection from our side and will not raise any issues in future.

1.If the said property is registered in her name , then being the owner of the self acquired property she has her right to transfer/sell the said land to anyone without taking consent of her legal owners. 

2. Yes , However a minor cannot be witness 

3. Not required , if she is the said property is registered in her name.