I believe there is a felt ring for either side that goes between the washer and the swingarm to seal out dirt. You could just buy some felt and make another set.
If the collar has much play in it, then you will notice it when you ride. If it is just minor play, then you'll be fine. I do recommend getting bronze bushings to replace the factory units though. It gives a nice handling improvement.
That grease might just blow out with a grease gun. If not, then you can boil it, soak it in carb dip, spray any solvent (WD40 included) on it and wrap it up in a plastic bag for a day or two, then soak it in simple green, or anything else that eats grease. It shouldn't be impenetrable.
Yes, you can replace the zerk. You don't need to unless it is broken though. There is nothing more annoying than removing zerk fittings because they prefer to break than be removed.
The swing arm came from the factory with copper inserts. They are okay, but not as good as the bronze units you can buy, and they might be worn. The copper units have a split in them that you might be able to see if you clean the area up. You really need to cut the unit in half to remove it. I did it with a sawzall. Don't worry too much about a nick or two in the swingarm if you cut it out, but don't cut it yourself if you don't have the "mechanic's touch".
You could reuse it all and just pack it full of grease. I would at least replace the felt gaskets, and probably the inserts if the collar is loose in them. If the bolt is really loose in the collar, then I would replace the collar too. However, all of those parts will still function fine for a daily rider for miles to come.
With regards to reusing parts, let me tell you a little story.
When I was 16, I bought my first car. It had a blown head gasket (1983 Honda Accord), so I had to fix that before driving it. It all went back together fine, except for a handful of VERY large bolts. I put them in my glove box for later. Well, I was back into that engine a few times over the years, and every time I brought out my spare bolts, and different bolts became the new spares. I never had a problem with the engine not being bolted together well, and it never fell out of the engine bay. That was a learning experience for me regarding the robustness of engine design (thank your local mechanical engineer).
The biggest learning experience came during a piston replacement. I was rebuilding my engine in the middle of winter in IL. It was cold... damned cold. I was in a hurry, and ended up gouging one of my crankshaft journals when reinstalling a piston/rod assembly. The gouge was 8mm long, 4 mm wide, and VERY deep, although it was surrounded with a good sealing surface all around. I think I took off half a mm of material at the deepest point. I just wanted the car back together, so I smoothed the edges of the gouge with emory cloth and reassembled. I never had an issue with the engine after that, and put on another 15k miles before I sold it.
I studied Mechanical Engineering in college and proceeded to design industrial gas turbines for GE (think massive jet engines that make upwards of 300,000 HP). I created a number of finite element mesh models, and came to realize the robustness of steel. It is just a very forgiving metal (nickel is a completely different matter).
So, don't sweat the small stuff with these engines. If it "looks" solid, then it is. If it looks "non-artistic", then fix it. If you are racing, then it is a different matter.
Camelman