Printing: Maximum 20% of a book
Downloading: 1-7 days
Text-to-Speach: No, Ebook Central doesn't have an integrated text-to-speech function.
You can use ClaroRead when reading online. You have to choose Scan > Scan web page and then mark the text you want to be read.
You can also use accessibility mode, in which pages of books are presented as text rather than images. If you use a screen reader such as JAWS, NVDA or VoiceOver instructions to turn on accessibility mode are available for reading when you enter the page.