Why did "She is one of my neighbors" not work here?
It could work for "È una" but uno lets you know that the neighbor is male.
Isn't "uno" a number in this case? "Lei e uno dei miei vicini" is incorrect?
Why uno here instead of un?
Because one(1) - uno
But a/an -un/una/uno/un' depending on the gender.
Right, uno is the only word that refers to the one person you're talking about. Snookered again.
Why doesn't "it is one..." work? Not sure why it has to be "he is..." as there's no other clue.
E could mean he or she so why say she is wrong