2 Items: Shared Garage between properties and Firing a RE agent.

First Item: I am interested in a property as a buy and hold. One issue that I am somewhat unsure about is that it shares a detached garage with the property next to it. As it is now the same owner has both properties. I could purchase the second property down the road but it wont be in the original sales agreement. I am going to require a maintenance agreement to be written and filed with the county. Anybody have any experience with such an arrangement?

Second Item: The agent I am dealing with continues to argue each point of the sales agreement that I want included. examples include the item above, arguing about the existence of a wood burning insert, arguing that he called my cell phone instead of my office phone etc. I am going to go with a different agent. Over reacting?