Concerning item 1, I don't think that should be a problem as long as it is kept dry. If you buy the boat pull it out and properly seal and mount it. Also the photo shows the bolts and nuts are black, which indicates the wrong type metal for the environment. You should use 304 SS bolts, nuts, & washers, you can use 316 SS but it tends to gull easier, and properly bed them when you replace them.
2. Class rules don't allow a roller furler, so just bite the bullet on that, and get a proper head stay, that you can adjust.
3. If you see surface rust on your keel bolts, they may have miss-matched nuts on the bolts. My 1985 J22 has 304SS keel bolts and that is what the nuts and washers should be. OR, what you are seeing may be salt water stains.