guardianship law

What is the name of your state? California

We are in the middle of a custody battle over my 11yo SD. Her current guardian is her grandfather who gave her away to family members at least twice without the courts knowledge or consent. (Her mother is deceased) The "host family" has had her for almost 5 years however had done nothing to secure their status during that time. The grandfather wants to withdraw as guardian and have the "host parents" granted successor guardians. We want guardianship terminated and her moved to live with us. It is my understanding that since there has been a prior determination of custody the standard used will be changed circumstances rather than the best interest of the child.

We have been deemed a fit household so that shouldnt be an issue. The only reason it has taken this long to do this is the $40,000 we have spent so far to get us where we are today.

Can anyone tell me if I am looking at the right standard especially since this is a California court?