combining CFP with HO4 to qualify my umbrella?

[Bo Ding]

I got un-renewed by my old ins and rejected by almost all ins companies (except for some crazy ones quoting me 10k/year) on my primary house, which is far from any fire zone but I had 2 claims on my 2 rentals (I am a small player so under my name not LLC) in the past 3 years so I got fked.

I have to purchase the California Fair Plan as fire ins, but it doesn't have liability, which I will need 300k for my umbrella. The "personal liability only insurance" is quite expensive at ~1000/year, while the renter's insurance (HO4) have 300k liability for less than 200/year. 

Is it OK to use HO4 to qualify my umbrella even it's my primary home? Like writing myself a $0 lease? 

Any other solutions except for the $1000 "personal liability only insurance"? 

Thank you!