If she has kennel cough she should be able to recover from that with antibiotics and good care .... an umbilical hernia is something that can sort of just happen for fluke reasons with certain puppies, even a championship show dog could produce a pup with an umbilical hernia... usually that is corrected during the spay surgery and is a fairly routine operation.
The diarrhea is what I am concerned about.. there are several reasons a puppy could get diarrhea the big 4 that come to mind are:
Worms- usually treated with oral worming medication
Parvo-can be cured if caught in time... but expensive and most of the time fatal
Distemper-Fatal there is currently no cure for distemper
Intestinal Blockage (could she have gotten into something she shouldn't have? Even eating part of a
chew toy or a blanket could be enough to cause a blockage)- fixed with surgery
Have you brought her around any other dogs or puppies recently? this includes any trips to places where other dogs could have gone to the bathroom and particularly places like Pet supply stores ... they are germ factories and should be 100% avoided until about 2 weeks AFTER the puppy has completed ALL sets of shots (around 4-5 months old depending on your vet).
I would contact the breeder after you get the test results and let them know the other puppies could be in danger and those other 2 owners need to be contacted.
Hope everything works out. Keep us UTD of her condition

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__________________
~Ignorance can be cured with education~
Mom to:
A little girl (6) and a little boy (4), and 2 dogs

Leo and

Gunner
Proud Coastie Sister!! 
My brother is in Virginia at FT school !!
RIP Ed

October 2000-November 2007