@pjw Thank you for answering me with so much detail. The answer to my second question was especially good; I understand the situations for the Palestinians born in various areas now.
As for the first question, it’s funny, because the one person I have ever asked the question, “Well, where should they go, then?” to (before you) was an American Jewish woman who is a progressive Democrat, “anti-racist,” etc. (She is someone I know IRL.) She told me, somewhat tersely, that the Palestinians should go to Jordan. She said the Jordanians had offered to have them. She seemed too upset to explain further, so I dropped it.