You can't claim start up expenses. You are confusing an LLC set up for the protection of the property owners with having a business. Your rental property is not a business unless you provide services, much like a motel or a bed and breakfast. It is a passive activity, reported on Schedule E, not Schedule C.
You will buy your property and the cost is it's basis. Any major improvements are added to the basis. You will claim income and expenses as of the day you have the property available for rent. This doesn't mean that it has to be rented. From that point on, your expenses are deductible. It is a good idea to have proof, such as newspaper ads or flyers or some sort or advertisement for a tenant.
