CONE/non-existence sufficient to override census?

My situation:

• GGG-GF born 1850 in Palermo, immigrated to US 1886
• GGG-GM born 1866 in Palermo, immigrated to US 1886
• Married each other in 1886 in Italy, a few months before the boat
• Birthed my GG-GM in 1888 in US
• G-GF, GM, M, and myself all born in US to US citizens or, in one case, an already-naturalized Italian

Naturalization issue: The 1900 and 1910 census lists my GGG-GF as naturalized, however I have not been able to find any naturalization documentation from local courts and NARA regional offices. Further, these census have a number of other incorrect information (e.g. wrong birth year, wrong immigration year, etc. that are different in each census) so I don't entirely trust them. (To be clear: it is definitely the correct person based on wife, children, etc)

My GGG-GM was listed as not naturalized in 1900 census and died 4 years later, so I think it's extremely unlikely she ever voluntarily naturalized.

I had thought a 1948 case would be the route to go, since I can prove there's no evidence of my GGG-GM voluntarily naturalizing. However, I was informed by a lawyer that the 1912 Italian law that women inherited the naturalization of their husbands has never been successfully challenged in court.

So now my question is: is having USCIS CONE and letters of non-existence from relevant NARA offices and local courts of my GGG-GF's naturalization papers sufficient to counteract the fact that the census (possibly incorrectly) says he was naturalized?

If so, it seems that would open up both the consulate and 1948 case options. If not, I think it's a dead end.

Thank you!