If I had to choose (but please don’t make me), I’d rather have a paddle that’s strong, light, and a suitable length for me and my boat, than a boat that’s perfectly suited to my body and destinations. No doubt both are important, and it is also important that the two are a good match for each other and for you. You might have some idea of what this entails if you’ve done some paddling with various equipment already, but it’s something of an evolution in most paddlers’ experience to find gear that works the best for them. Any time I’ve swapped boats with someone, my paddle always stays in hand. Next time you’re out paddling, count the number of strokes you take per minute (or look it up online). Now extend that into a few hours on the water, and you’ll start to realize that this is perhaps the most critical component in your paddling gear. It’s akin to the tires on a car. You can have all the power, stability, and braking you want but if the interface between the tires and the road is compromised then you end up in the ditch just the same.
I have to give credit to you for giving this much more consideration and thought than most people seem to. Unfortunately, you may be a victim of “paralysis by over analysis” due to the very grey nature of many decisions to be made. I usually suggest trying lots of boats to someone who’s been out once or twice but otherwise clueless. In this case you’re not completely new to it, and you’re clearly good at considering the variables in the equation. If you can narrow your choices to a handful of boats that seem to fit your size and goals, you can pick one from that group using less stringent criteria - like what’s on sale, or what’s close by, or in a colour that stimulates you. Second hand availability has always been a factor in my own purchasing decisions. You’re likely to get a boat that serves you fairly well for a while. You may or may not find that you want to take things further, and need to get a different boat in a year or two. This seems par for the course in your situation and the reason why people who do this a lot have more than one boat and tend to buy and sell them more often than seems rational. A well-stored boat that can’t be found in your local big box store’s weekly flyer will also retain much of it’s resale value - especially if you’ve purchased it used in the first place.
Regarding the boat, I’d never again own anything that didn’t have sealed bulkheads front and rear. I sold a River Runner R5 a while back largely for this reason. I don’t want to mess with, or have to trust, flotation bags when I paddle beyond the shoreline. I also prefer long boats that track well, even for small waterways where I get odd looks amidst the short recreational boats. At first the length is cumbersome, but with time and skill I can maneuver my 17’8" Impex Assateague better in tight spots than many novices in short recreational boats. Clearly, there are limits though. If I could find a short boat that didn’t plow through the water, still tracked straight, held camping gear for a week plus, and floated my 225 lbs, 6’2" frame, I’d give it strong consideration. But alas, such a thing defies the laws of physics such as our current science and materials are.