Type 1 pfd is the most likely to keep your head out of the water. OK on a boat but I wouldn't like to paddle in one. Maybe a self inflating vest but if you get wet, you'll end up looking like the michelin man
. If you are kayaking close to ocean washes or in any fast moving water, maybe a helmet is the go. If it's boat traffic that is the concern, a flag mounted with a light aids visibility. Apart from that, it's safest to always go kayaking/canoeing with a mate.
All the best.