Home Owners Insurance And Real Estate

Location: California

Forewarning this is a long story:

We bought a house and the day we got our keys and walked into the house it was flooded. The previous owner took responsibility because he saw that it had clearly already been flooding before we got the keys. (House was vacant for a few months) and his insurance accepted the claim. The insurance company took over two months to look at the damage and approve. Since they took so long the damage has gotten worse and tons of mold has been found. The remediation people are now having to remove dry wall and even some beams and other major parts. They may even need to remove us from the house for a while now because they are having to remove our hot water heater and this is only the beginning sort of the demo.
Other issues:
The date we moved in a lady was here in the driveway looking in the windows. When I asked her who she was she got all weird and left. Then when we walked in and saw the the flood we called our agent and he had the listing agent drive over to help us out and she proceeded to give us information we weren’t ever made aware of from her or our agent. We found out that there was a squatter (YOU GUESSED IT..the lady who was here at the house looking in the windows) who had been living in the house for years and it took two years for her to be evicted by the sheriffs and there had been multiple break ins into the house after she was removed and it was vacant. Someone even stole new carpet from a room. It was so bad they ended up installing a Security system.
Is there any type of legal action we can take for any of this? It has caused immense distress dealing with these things. I don’t feel safe in my home. I just had our third child 3 days after we moved in and I spend the majority of my nights in fear someone will try to break in. I am also extremely terrified for my families health and well being knowing part of our house has mold.