Bad behavior rubbing off

I have two small mixed breed puppies.  Probably Shih Tzu/Terrier type dogs.  They were supposed to be here temporarily due to a death in the family but thing haven't worked out so but their owners can't take them back right now.   The problem is they are dog aggressive/cat aggressive, yappy.  I did a puppy class with them but neither one did very well.  Their behavior is rubbing off on my Chow.  Freddy has always been  difficult but never dog aggressive .  When I take all three out together they are embarrasing.   About two weeks ago a Lab jumped out of a car window and tried to attack the puppies.  Freddy tried to fight him and bit me instead.  I am just frustrated because the little guys start trouble with their barking and get Freddy all worked up too.  There are dog events this month and I am now nervous to take Freddy.  I don't know if it's just the puppies or him reaching adulthood.

Does anyone have any suggestions on controlling them when they are together or should I only take them out individually?  How do you manage and train a multiple dog household?  They need to walk every night to sleep so it's easier to take all three at once.  I need to start thinking of them as mine and come up with a plan so I can actually start enjoying having them here.