For this I put "She is cold". I'm confused about the differences between she and it here.
There is no difference, in a real conversation you'd work out from context whether the speaker meant she or it.
Why is it "i"? Isn't that usually "she"?
Because weather is feminine
i = "she" or "[feminine] it"
If talking about a person's temperature -- as in "She is cold" -- does this phase work, or is it idiomatically only the weather? (And if weather only would the normal construction for a person be something else, as in "She is feeling cold?")
Yep, you'd use the same sentence.
If "Tha i fuar" is both "it is cold" and "she is cold", how do we say "he is cold"?
?Tha e fuar?
How would you then say "It's cold and she's cold" ?
Sounds like the great basis for a pun