A little investigation may be in order to determine whether in a divorce the life insurance policy is still validly payable to the ex-wife. What does the divorce decree say? Is there a state law that essentially says that all designations to spouses during marriage are void at the date of divorce? Was the ex-spouse named on the policy after the date of divorce? If so, then she likely is the rightful recipient of the death proceeds. Is the value of the death proceeds worth pursuing? The investigation should be done sooner than later so that if the ex-wife is not to receive, then the life insurance company should be contacted ASAP. Otherwise if the life insurance company pays the proceeds, then you likely will have to resort to going after the ex-wife. Who knows by the time you get to her, she may have spent it all. In regards to wrongful payment by the life insurance company, that may be a hard row to hoe. There may be protections for the life insurance company.
Your question doesn't actually establish that the estate was insolvent. Under most states' laws if the beneficiary of the life insurance is an ex-wife, then the beneficiary designation is void. However, if she was named after the divorce, or pursuant to court order in the divorce it is still valid. IF a probate is opened the creditors will have a certain period of time (typically 4months to a year) to make a claim. If they do not, and your state's notice procedures were followed, then they are barred from making a claim.
You need to open a probate so that you can obtain a judges order specifying who gets paid and how much. Getting an attorney to help won't cost you anything because all of the assets will be sopped up by creditors with higher priority then you. Fortunately, under Wisconsin Law, the attorney gets paid first, along witht the accountant who does the tax return, so you should be able to get someone to take your case.