If I purchase an ebook, can I send the original copy to other readers? I would NOT copy the original file.

Only one user would access the file at once. It would be like Netlix renting one movie to multiple people, as soon as one is done with it, the other can use it. The only difference is that instead of sending it through the mail, I would send the entire original file, not a copy, to the user over the internet and wait for them to send it back before I send it to someone else.