Speak with the lumber department as most store will cut this product for a fee.
Yes, it can be used for many applications but is not ground contact rated.
Home Depot had a very good selection.
Your choice of Prime # 2 and better are excellant choices for outdoor furniture. You will want to stain and finish the wood once project is constructed. You also will need to put something on the wood to prevent wood rot. Once a year is recommended for refinishing your out door wood projects.
Home Depot has many types of wood stain that can be used to achieve the redwood look. They are good quality wood stains.
General public price I believe. You can always ask for contractors pricing.
Home Depot has all standard sizes in all construction wood. Yes, they will cut your wood for you. Simply find an associate in the wood area who will help you. Home Depot has 4 x 4 x 10'. Ask an associate.
yes, Home Depot has all construction sizes of board sizes, stud sizes and plywoods.