I have been checking a few references, and can find no absolute confirmation about the puzzle cars. The photo shows 15 cars, and other pictures of the start do not show any more than that number. The "certain site" which has been referred to claims that there were only 13 starters - perhaps they were going by official records, and that the organisers allowed 2 cars to actually start which had been damaged in practice, but fixed in time for the start. These would be Cattina's Alfa, and almost certainly one of the Lancia Aprilia entries - there's nothing in the puzzle photo which looks like an additional Maserati. I reckon they would have been placed by the organisers at the back of the grid - the powerful Alfa has already made up ground, but the puzzle Lancia #12, is still there. Could this be the car of Danzi?
Although the "certain site" is not always accurate, we have to believe that some of the records are correct. They claim that 2 Aprilia cars started 5th (Adanti) and 9th (Bianchi) on the grid. I don't believe for one moment that a tuned production engine would achieve a starting-grid place of 5th against Ferrari, Maserati, Alfa etc opposition, but the 9th place would fit in with the Touring-bodied car in #8 so this could be Aldo Bianchi. That means that the "Jaray-style" berlinetta #9 is being driven by Enrico Adanti.
Those special-bodied Aprilias were not really very fast. Aldo Bianchi won his class in the 1947 Mille Miglia, but he finished almost 2 hours behind the winner of the 1100cc class (which was some guy called Nuvolari whoever he was). I'm only guessing again. but the 2 races were in the same year, so it's probably the same car - if anyone has photos of the '47 MM they may be able to solve this.
I'm still trying to find absolute proof......