A landlord's insurance policy will be suffice. Insurance covers both the property and the business. I typically get a quote from my broker during the latter stages of closing and add the property to my policy shortly after closing.
When you mention business license, it appears you mean business entity. You will need to create a business if you want the property to be registered to the business at the time of closing. You can do a subject to formation deal if you want to know if the property has a clean title before starting the business. In the buyer field on the Purchase Agreement, you list the company name (be sure to research its availability) and in parenthesis thereafter, you write "subject to formation." Once you verify a clean title, you can create the company and then provide the Articles of Incorporation to the title company.
In terms of your third question, I believe it depends on the holding company. Are you looking to purchase properties under the same entity in which your PA properties are held or are you creating separate entities by each state?
