In pic 1, that's just a stop knot so you don't lose the rode and anchor overboard if you drop it accidentally. You want to tie the anchor off at a cleat if you are into the line or use a snubber if you are shallow enough to still have chain over your rail. That however is not what that attachment is for, that's where you hang your anchor.
Well you don't show many pictures of the line, but from the little I see I would replace the line, at the very least learn how to make an eye splice with some spare line. Do it 5 or 6 times or until you can do it beautifully. Once you can do that, then buy a new thimble and splice the line around the thimble. A trick to splicing tight around a thimble is to pull the line really tight, then pull a zip-tie around the rope where the jaws of the thimble come together. Then tie a tight eye splice and you have yourself a new and properly tackled anchor line. Do NOT use bare rope to the chain or to the shackle; it will wear through within a week or two (assuming constant anchoring).
That shackle doesn't have any wire on it. I'ts probably seized, and so ok, but you don't want to count on that. When you put the shackle back around the chain and through the eye splice, you want to tighten the bolt down, and then tie it off with a round or two of stainless wire (it's called seizing wire). Any stainless of 304 or 316 will do, just check it from time to time. That's why there is a hole at the end of the bolt; seizing wire stops the bolt from unscrewing.
The chain looks fine, but I would bring it to a plater and have it Hot Dip Galvanized. It'll cost a WHOLE lot less than new chain.
I'd still replace that line, but learn to splice and splice well. it will save you quite a few Dollars if you don't have to buy it pre-spliced.