To answer your questions-
1. Even if Alessandro was originally from somewhere else, his records in Cefala` would not have indicated that he was of unknown parentage unless he actually was. To marry, for example, he would have had to provide a copy of his birth act. Regardless of where he was born, the birth act of an abandoned infant is basically a description of the abandonment and discovery by someone=for example, if he was left on someone's doorstep, then that info would be in his birth act, including a description of articles of clothing, religious medals, etc, that had been left with him. Or he may have been abandoned at the wheel. There were institutions in Italy that were established so that children could be anonymously abandoned. The institution would have a mechanism known as a wheel. The person abandoning the child would place the infant on the wheel and ring a bell. A nun, or some person inside the institution whose job it was to receive the abandoned infants, would than pull a cord to rotate the wheel and bring the infant safely inside. These institutions were established to eradicate the problem of children being abandoned in the streets or in the fields which, in older centuries, had been done. Before the establishment of such facilities, abandoned infants were often eaten by animals or would die from exposure to the elements. Rarely would someone take an infant home, as many people were poor and already had big families, so an infant was just an additional mouth to feed. In previous centuries, however, an older child abandoned in the streets had a better chance of being taken in by a family, than did an infant, as he could serve as farm labor or help with household chores.
2. I don't know about the surname Albian. As I told you, since Alessandro was abandoned, it was an invented or made up surname. If we locate his birth record, you might find the town official giving variations of this same surname to the children whose births were recorded right before or after his. The surname Dioguardi, however, is a compound name made up of two Italian words -Dio which is God and guardi which means watch. I know there is a surname spelled as Diotiguardi which means God watch over you, so I think Dioguardi is just a shortened variation of that surname leaving out the "ti" for the word "you."
3.Here's a link to the records available for the town of Cefala`. The ones with the little camera are the records currently online. The other microfilms have to be rented and used at a local family history center.
https://familysearch.org/search/catalog ... 20Diana%22
https://familysearch.org/search/catalog ... %20Library