I am renting and owning a house at the same time. Do I need renter's insurance and homeowner's insurance?

Hi, I have a home in Texas but is living in Washington. My parents have been living with me since I got it. The home is in my name and still paying mortgage. I have insurance on this home and auto with "Insurance A".

Now, I've moved to Washington and is renting an apartment. I got renter's insurance with a company at the office (Now called Insurance B). I called and switch my auto to WA policy. Insurance A asked if I needed renter's insurance and am I still owning the home in Texas? I didn't tell them that my parents are staying there. Only say that someone is taking care of the home regularly. They also say my homeowner and renter's insurance must be in one company.

I told them I don't need renter's insurance because I have one with Insurance B and I don't know what I'm planing to do the home in Texas and will contact them later.

I don't know how long I'm gonna be here in Washington and do not know if I will sell my home in Texas in the future. But as for now, I am gonna stay here for at least 1 year and do not plan to sell the Texas home within the year.

My questions:

1. Why I can't have two policies with two different companies? When one is for my home and one for my apartment?

2. If I do tell them that my parents are staying at my house, will they make me turn my homeowner's insurance policy to rental property insurance? My parents are not giving me any money to be there.

3. What are some options I have to sort this out, homeowner, renter's, and auto insurance?

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