@Kwok Wong - All great questions! Regarding closing under a LLC, you can establish a LLC once you have a property under contract if that is prerogative. Normally, I do not establish LLCs until I have the property under contract and I am deep into the closing process.
Regarding if you need a LLC, it all depends on your risk tolerance. If it's a residential property, normally the loan will be more expensive to close directly under a LLC vs. your personal name hence the cost of debt tends to be higher. You can always move it under a LLC once you close as well.
Additionally, you always have the option of loading up on a ton of insurance and putting it under your name. Typically, you can purchase an umbrella policy for as little as $300-600 annually that offers a million dollars of liability coverage. Combined with your homeowners insurance, you can have as much as $1.5 to $2 mil of liability coverage for a property. From a financial perspective, loading up on insurance is more adventengeous than a LLC because if a claim arises, I'd rather file an insurance claim that give up the equity I built in a lawsuit. You of course can utilize both strategies however the adminstrative costs associated with owning the property becomes higher. Just a few thoughts, good luck!