My advice to you is keep collecting all the materials against your wife and father in law for future use.
Police can not arrest you in family matter directly because Apex Court has clearly mentioned about dealing with the matter of Domestic Violence reported by wife against the husband.
In case of complaint by your wife against you ,Police are bound to give you notice .
Based on that notice approach Sessions Court for Anticipatory Bail application and attach all evidence for your success.
Blanket order can't be granted by any court in India.
Your relief can be granted by Sessions Court, hence no need to approach High Court.
You may file a Complaint ,in writing , to Local Police and Copy to SSP citing threats to you by your Father in law and in-laws during proceedings before Punchayat.
If Police and SSP do not take action of your complaint then approach nearest Judicial Magistrate for direction to police to register your FIR against your in-laws.
If your wife doesn't want you with her as life partner and she is in love with other man prior to your marriage then file divorce before Court on the grounds of adultry and am sure you would succeed.
This way you can out wit your wife and in-laws legally and hold your head with pride.
No threat to you and your job.
All the best and Good luck.