Stay relief is always required to commence or continue an action against property of the estate. "Property of the estate" is a defined term pursuant to 11 U.S.C. Section 541. Your question is whether since the property is not truly property of the estate (at least based upon your representation that it is no), then is stay relief required. Even if you are correct and the property is not legally hers, there is no determination by a court of competent jurisdiction, and, therefore, you should, at least, seek a "comfort Order". Sanctions for stay violations can be hefty, therefore, it is incumbent upon you to tread very carefully (and hire a qualified bankruptcy attorney in California to assist you)!
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You can't proceed against someone in bankruptcy without the approval of the bankruptcy court, called a "lift stay." You will need a bankruptcy attorney representation. Hope this perspective helps!
In addition to the advice given by others about bankruptcy procedure, I suggest that you consult a real estate attorney about how to get the title issue cleared up. I don't claim to know CA law, but in CT or Mass we would do deeds between the parties to clarify the title if all concerned are co-operative, otherwise you would have to go to court with an action to quiet title.
This response is intended to give a general overview of the law and should not be treated as legal advice. There are too many factual issues and exceptions in the law to provide definitive conclusions about your circumstances.