Legal Question in Real Estate Law in California

On #1, I would say probably not, but licensing businesses is a local (city or county) basis and you can easily find out by calling the business-license department of the city to see if San Diego has any licensing or registration requirements for residential landlords. Your call should also include asking whether there is anything you need to do to comply with local rent-control reguations, if any, as a new landlord.

As to #2, a tenant leaving at the expiration of a lease for a definite term is not required to give notice, as both landlord and tenant are presumed to know that when a lease expires, the tenant must leave (assuming no renewal). However, if the situation involves a month-to-month rental rather than a lease for a definite term, the tenant is usually required by rental agreement or statute to give 30 days' prior notice. See Civil Code section 1946 (and you might also note sections 1945 and 1946.1 which discuss related subjects).