The stern compartment and bulkhead should provide good flotation, so long as the hatch does not become dislodged. You can put an airbag in the stern compartment “just in case” if you are not carrying gear and anticipate paddling water that might give you trouble. I assume this boat has a vertical minicell pillar running down the center of the bow. This supports the deck and reduces the chances of the deck collapsing on your legs in a pin, but also will provide enough flotation to prevent the Cleopatra’s Needle effect. And unless you have removed foam from the boat, your boat will not sink.
However, a lot of kayaks do not have an overabundance of flotation, and if completely swamped will ride relatively low in the water. Kayaks with a lot more flotation in the stern than the bow tend to wallow nose down in the current. These can be difficult to rescue from current. Whitewater kayaks became very short over a few decades, and many playboats now have room only for small bags in the stern, and no room at all in the front. The upshot is that in these boats, the cockpit area which is occupied by your body and cannot be filled with flotation, comprises a far greater percentage of the internal volume of the kayak than it did in old school, long and pointy whitewater kayaks.
The problem with a 12 foot kayak is that you are not going to have room for anything but pretty small bags in the bow. If you have a central pillar, you will need a pair of bow “split” bags. But any flotation that is not secured to the boat will want to try to float out if you swamp, or blow out if you car top. Flotation bags have corner grommets or nylon loops sewn into the corners. One way to secure a set of bow bags is to push a short length of 3/4" diameter PVC pipe through your front pillar at the location the rear grommets or tie down points will be with the bags inflated. Be aware that depending on the bag size and your foot length, you may not be able to fully inflate the bags. Run a short length of paracord through the PVC pipe and secure each end to a bag tie down point. This is somewhat easier said than done, because you will need to be working inside the bow of the kayak. Some people drill small holes through the deck near the bow stem on each side of the pillar, and feed cord through to tie onto the nose grommet of the bags.
A recreational size cockpit such as that kayak has is not really well-suited for a spray skirt. You might possibly be able to find a large skirt to fit it, but it will have a lot of deck area to catch water, and will relatively easily implode if you should capsize in heavy water. But then again, that kayak is not really designed for such use.