If you are asking what happens if a person dies without a will and leaves a spouse and two adult children (and no predeceased children with their own surviving children), the answer is that under Nevada law the estate will pass 1/3 to each party subject to a number of "ifs."
The major "if" is that if property is in some form that automatically passes upon death to someone else it is outside the probate estate. So, for example, a joint bank account or a home owned as joint tenants passes to the other joint owner automatically.
You specifically ask about Minnesota LLC's. If your father was the sole owner of the LLC, the LLC should have to go thru probate subject to the 3 way distribution. Now, if the LLC is holding Minnesota real estate, we may be talking about a Minnesota probate subject to the laws of Minnesota for property passing without a will. I'd need more details about the LLC.
Another big "if" is if Wife #2 can claim that some of your father's estate, even if in his sole name, is really community property.