Hi Jared.
First of all, a warning. The muzzleloader bug is infectious. When a guy gets his first muzzleloader he runs the risk of becoming addicted. If that happens you will have an overwhelming need to acquire additional guns, equipment and shooting supplies. So getting the first one is not a decision to be taken lightly.
As for the two kits linked in your post, I suggest you eliminate the blunderbuss from consideration at this time. While it may be fun to shoot a few times, and will certainly make noise and smoke and possibly even hit something now and then, it's primarily a novelty gun. it's not a gun a guy would use often. And it certainly is not well suited to target shooting.
The Traditions Kentucky rifle is a pretty good deal and not a bad gun for plinking, target shooting or hunting. Putting that kit together would be interesting and fun for a guy who likes to build stuff. And you should end up with a functional gun that's not only fun to shoot, but much more practical than a blunderbuss.
Now there's the question of whether one's first traditional muzzle loader should be flint or percussion. Flintlocks can be finicky and have a greater learning curve than caplocks. You might consider the following kit.
TRADITIONS STL HAWKEN RIFLE KIT .50 CAL/ RAW HARDWOOD - Graf & Sons (grafs.com)
I generally recommend caplocks for a new muzzleloader shooter, especially when I don't personally know the individual's temperament or background. Other shooters may disagree with me on that point. There's nothing wrong with going with a flintlock as an introductory gun - it's a personal choice. But there's a greater chance of disappointment/frustration with the flinter.