1. No.
No is the answer, if she cannot claim any share in your own property then how do you think that she can claim any right in your parents property beyond you. In fact you yourself cannot claim a share in your parents's properties during their lifetime, so just relax, she cannot legally claim anything.
2. The absolute owners of a property can dispose/transfer/bequeath their properties in any manner of their choice, nobody can compel them to do anything in their favor.
3. Your wife cannot in any any manner challenge the Will. Will is no doubt not necessary to be registered as mandatory, but registered will cannot be challenged in any manner by anyone even having a vested interest over it.
4. The charges and lawyer fee cannot be predicted, it depends on the the lawyer who you would like to engage.
5. There are various judgments from supreme court to high courts stating that highly qualified women cannot sit idle at home to claim maintenance.
The maintenance case shall be decided on how both the parties present their version before court.
6. NO