I made some progress using the three steps that you suggested. I can open the .ASCM book I downloaded from the Mac/ADE to the Nook, as well as previously downloaded B&N books, using ADE. I open the book by opening the Nook device, going to the appropriate directory, and clicking on the file number (all the books are listed by file numbers, no titles). But when I disconnect the Nook form the Mac only B&N books are shown by title, not the one I downloaded.
I don't know how to check time and time zones on the (original edition) Nook.
I did authorize the Nook from ADE.