First, its good you have 100/300 limits as this is more than the minimum limits I usually see most people carry. Its very common for your insurance company to deny to pay an initial demand of full policy limits, as they want to pay as little as possible. Most cases like this resolve within policy limits, and you are ok for now. If you are stressing over the deal, you can always hire a local attorney to assist you.
I'm not licensed in CA, but I could never under the facts you stated recommend to a client of mine to settle for less than $75K, and I certainly would be willing to take it to trial where a jury verdict could easily exceed the policy limits. You have a solid case and you need to get some professional help from a personal injury attorney in your state. If your insurance company does not act right, then you may also have a bad faith claim against them too.
Generally speaking no. A good rule of thumb to remember is that if something is titled (like a car) then the home owners coverage does not apply. There are exceptions, but they are rare.
Lots of people think that because their motorcycle was parked int he garage of their home, it will be covered by their home owners insurance if the house burns down, and this simply is not true since the motorcycle is titled.
Again, there are exceptions, so contact your local attorney and let him advise you....
You need to hire a criminal defense attorney if you want to have any real chance of beating the charge. A shoplifting charge is serious also because it is a charge that stacks in offense, for example 1st, 2nd, 3rd offense, and a 3rd offense is a felony regardless of whether its under $500 limit.