A sloop was the largest fighting vessel commanded by an officer of lower rank than a captain and carried less than 20 guns. In the 17th century sloops had three masts but early in the 18th century, sloops were two-masted with 8?14 guns. The guns would probably have been iron, though there was occasionally a bronze gun or two but was not the norm.
As for valuable artifacts, well everything has a value, but if you are looking for high value items then you would need to know the name of the ship where it was going what had it done previously. Maybe it was taking loot back for the Queen, more probably she was really a privateer in which case she may have taken some ships previously and was carrying treasure. How did she sink was she abandoned, sunk in a battle? etc
But the sum total is you need to research the ship now to find the story and maybe provenance.
As for the cannon balls I am sure someone will chip and let you know the best way. Incidentally what diameter are they, from that you can asses the caliber of the guns (there would be more than one caliber on board).