Sonya for you excellent posts giving Tara a wealth of information she may (or may not) have had on hand from Wendy. You can never have too much information when it comes to helping these little mommies whelp. Yes, letting the newborn pup nurse inbetween births will not only give the pup vital early nutrition, but will also help to stimulate mom's contractions for the next pup.
Tara I am sure Zoe is feeling your calmness now and that is going to help her stay calm also. Maybe now she will be able to be confident enough to be able to have these puppies knowing you are there to help her even though her mommy (Wendy) could not be.
Good luck and hugs to you......we're all here with you and are here to help!