Purchase Agreement Before Probate Is Completed California

[Tou Vang]

If a person passed away, from what I've heard in the state of California, it looks like the family has to wait a mini of 40 days before they can proceed with the estate hearing.

If I knew that the person who passed away (Person A) has left the will of the property to one of the family member (Person B).

My question are:

1) Can I enter into a purchase agreement with Person B prior to the estate hearing with the contingency that Person B inheriting the property?

2) How long can you extend the purchase agreement? I typically see 30 - 45 day but have heard of 90 days before.