What reason is there to keep Lenora di Genova connected as daughter of Lorenzo de' Medici, il Vecchio
Serious family researchers cannot find her (see notes below).
Also, are the dates screwy?
https://www.italiangenealogy.com/forum/topic/17041
Yes, I am aware of this. One branch of my family is descended from Jacopo di Genova and Leonora de Medici, and they are included in the family history prepared by my father over a period of 40 years. The document to which you are referring is available in both the Virginia State Library and (in extracts) at the University of Virginia Library. At one time, notes on Jacopo were also available at http://www.mindspring.com/~arturo/gannaway.htm, but when I just went to check that link it was no longer active.
I don't have anything anything further back. The Lorenzo mentioned earlier in this chain ("The Elder") was born in 1395, but both Jacopo and Leonora were born in Florence in 1544, with Ricardo (as you know) being born in 1564; I'm trying to source the disconnect. She would have been the daughter of someone from a later generation than Lorenzo the Magnificent.