Good idea. It's called a range rod. Leave the factory rod in the gun where it will look good and get a solid brass range rod. And add a short starter, mandatory.
Not mandatory for a long gun, but convenient. A decapper is a good pocket knife. To save some money, leave this until later.
Dedicated cleaning kit - which should have oil, grease for the nipple, and cleaning patches
Ummm, well, ok. Add the cleaning jag as has already been mentioned. Typically these 'kits' don't come already assembled for black powder like they do for smokeless guns - you'll need to put it together, but you're on the right track.
Yep.
powder horn (a brass one, not a hollowed out horn- not yet anyway)
It's called a powder flask.
some .015 patches for my .49- round balls
Ok to start out, but you'll eventually want to experiment with other thicknesses.
ball remover/patch grabber - but i've heard you can just tickle powder down the flashhole once the nipple is removed but I've done NO research about the... safety of this.
The ball remover and patch remover are two separate tools; good to get both. Putting powder under the nipple to remove a stuck ball is just as safe as shooting the gun in the first place. Just observe all the same safety rules, including the one about making sure the ball is seated on the powder.
some of that magic foam to clean the gun - brand unknown but I'm sure it's out there
Yeah, it's out there. So is the Brooklyn Bridge and cheap waterfront land in Florida. One word, repeat after me: water. Plain old water. Works just fine and costs a lot less.
and last: a sling that connects to the ramrod but I haven't found one yet in my price range (< $45) that i know will work, I literally just googled it for the first time today and have done no further research.
Ok, but if you're target shooting you won't ever use it. It'll just get in the way. If you want an authentic sling that doesn't require swivels, don't leave it on the gun during storage or you'll find it changes the finish under it.