An LLC could be created by either an asset transfer, a stock transfer, or a liquidation. There is potential gain on the transfer of assets under any of these three methods.
Regardless, you need to determine the basis of stock on DOD based on fmv for the heir(s).
My first question would be what type of business is this? Secondly, I would request a list of assets and liabilities.
In regards to depreciation, you can probably safely assume that most any 1245 assets reported on the last return nine years ago have been fully depreciated. Do they have any records or bank statements for the following years to determine any additional assets purchased? Is there a manager or key employee that might have some knowledge of such?
Does the company own a building? If so the cost and date of purchase should be available from the courthouse.
You mentioned shareholder salary, have payroll taxes and reports been filed? How about personal tax returns?
Also, you might have estate tax issues to address.
Offhand, I do not see a way around filing a current and past returns, with or without depreciation; the estate attorney might also wish to see copies.