Les:
I am sorry to hear about your experience with a Bakersfield lawyer. I cannot comment on what your lawyer has done or is doing but I hopefully can help you understand the process.
I assume that the interests that you inherited were not included in a probate or other trust from the decedent and therefore the interest is currently not in your and your sister’s names. As such, the procedure is to prepare an Affidavit re: Real Property of Small Value IF the property is valued at less than $50,000. Otherwise, a more complex probate process is required.
In California, mineral interests are valued on the worth of the proven reserves. Thus, if the minerals are not producing, the value is almost worth zero and typically will be between $5 and $15 per net mineral acre. Here, however, it appears that you have producing minerals. Therefore, a valuation is required. Such valuation is highly technical in nature as you can imagine given that it requires a petroleum engineer to determine the worth of those proven reserves as a whole and then to determine your fractional interest in them based upon the information that you have already obtained. The probate referee is the person who values these interests when it is a probate matter. The probate referees here, however, are likely not well versed in such valuations. If the valuation needs to be done and submitted to the probate referee, then I recommend hiring a person who can do such valuation. If the probate referee will prepare the valuation it sounds as if you may have enough information to submit it to the referee.
I am not a probate lawyer but an oil and gas lawyer. I have prepared these documents and have relationships with petroleum engineers who can prepare the valuations and with the local probate referee who has been very forthcoming regarding the procedures necessary to finalize the transfer from a decedent to his/her heirs.
I hope this helps.