What are some similar things about the Tuck and Foster family in Tuck Everlasting?

I think that the biggest similarity between the two families is their care for Winnie Foster.  Both the Fosters and the Tucks clearly care for her and her safety.  Mr. and Mrs. Foster are not portrayed in a very positive light.  They are very over protective parents that do not let Winnie do much wandering on her own.  It's a bit oppressive, but it has to be argued that they clearly care for her safety and well being.  They do not want to see her hurt.  The same is true of the Tuck family.  They are a bit looser in their rules with each other and toward Winnie, but they absolutely would give their lives to protect Winnie from any sort of danger.  

Another similarity is a very surface level, literal similarity.  The Foster and Tuck families are families with a still together mother and father. That's a big deal to me as a reader, because I don't see that too often in newer teen literature.  Take The Hunger Games or Twilight series for example.  Bella's parents are divorced, and Katniss's mother is a single mother.