That could all be true. It may also be true that they were armed when they were chartered. It hardly changes the point that most of the Fleet was belligerent.
doubtful that the navy would make any effort to arm a chartered tug. Arming a ship built for commercial service requires a little more than strapping a 32 pounder to the deck. A 32 pounder weights 3 tons. The deck beams beneath it has to be reinforced as well as the frames where the gun is positioned. This work is done below deck to support the weight. A suitable magazine for the gun powder has to be built.