What is the correct question tag for "YOur family lives in California, ...?"
As the tittle mentioned, my friends and I got confused for the right answer. Of course, we can use other way to talk about this but what is the correct tag question for this one?
In this case, "family" is singular because all the family members are living under one roof.

Question

What is the correct question tag for "YOur family lives in California, ...?"
As the tittle mentioned, my friends and I got confused for the right answer. Of course, we can use other way to talk about this but what is the correct tag question for this one?
In this case, "family" is  singular  because all the family members are living under one roof.

Answer

... don't they?

Tags have the opposite sense of the statement.

The family = group of people so they (not it - it is for inanimate objects).

Answer

To my American ear,  it will usually sound better to say "don't they" for a family. But there could be instances where the family is really acting as a single unit, and "doesn't it" would be ok, but not necessary.
For example, let's say there is a holiday get-together attended by many families. The tradition is that each family brings a different dessert.
"Your family always brings apple pie, doesn't it?"

Answer

When you talk about a family, you refer to a group or a collective noun.so, in this case,I would treat "your family "as a group. Therefore, In my opinion, 
Your family lives in carlifoni, doesn't it?

Answer

Both "doesn't it" and "don't they" can be used in this case. "It" is not exclusively for inanimate objects. "It" can be used for gender-neutral or gender-ambiguous words, such as "family". "They" can also be used because a family is a group of individuals.