If your family keep feeding her with processed meats like chicken sausage they will shorten her life -- they are full of fats and nitrite preservatives that are NOT healthy and she will not be getting a balanced complete diet that is extremely important while she is a puppy in particular!!
Maybe the whole family needs to go in for a serious talk with the vet about how they are cutting short her life by doing this. I'd stop buying processed meats as well so that if the family cannot restrain themselves, they don;t get those foods either. That's better for their health, too!
You do need to stop trying to add in different foods (you can give a varied diet but better to do this when she is older and not holding out for food) and if your family is serious about her having a long and healthy life they absolutely MUST stop random feeding or her diet will be seriously short on the nutrients she needs and she will get fat -- which a recent study shows cuts on average 3-4 YEARS off a dog's life. This breed almost all get heart disease eventually -- some are prone to it very early -- which means any ounce of extra weight limits their lifespan, too, as the heart must work harder to pump blood. Please, please tell them to take her health more seriously -- I know they will want her to be with you for as long as possible.
Read this post for more information on managing a fnicky eater:
http://board.cavaliertalk.com/showthread.php?t=24168
The problem will get far worse if this isn't managed right away so do be strong and stick with giving her a healthy, balanced diet.
Her future depends on everyone being responsible, not selfishly feeding her whatever they want.
There are several threads in the Caring for your Cavalier section on what to feed -- have a read of those threads as that will give you ideas of what is nutritious and healthy to add to her diet. But really it is so, so crucial for people to STOP FEEDING HER EXTRA TREATS and additional meals!!! That is the fastest way to having a fat, unhealthy dog with a shortened lifespan.