I've seen the entire franchise several times, and I have to disagree with you about Part II being the best. It kind of felt like the first movie repeated with a bigger budget, without much original thought. I did like Mrs. Voorhees' head in the cabin, that was nice and creepy. I liked the use of the campfire story as a way to present a lot of exposition and backstory for new viewers. I didn't like the copious use of flashbacks in the opening teaser, it dragged on way too long. The killing of Alice is really disconnected from the rest of the story and doesn't really make sense. Why did Jason track her to her home instead of just killing her at the lake?
This is where they really confused the mythology, but I don't think they were thinking about mythology or that there would one day be 12 movies (and counting) in the series, so I kind of give it a pass. Still, the first movie ended with Jason as a boy in the lake. Even five years later he wouldn't be as big as he is. Why would he not age for 20 years under the lake but now start aging and growing again? The most obvious answer is that the boy Jason jumping out of the lake was just a dream. The real Jason never really drowned, he was thought dead by his mother but has been living in the woods all these years, now grown to a man. In the campfire story they say Jason was there hiding, watching his mother be killed in the first movie and now is out for revenge. If Jason was alive all these years, why did he never reconnect with his mother? It doesn't really make sense. I don't think there's any way to make sense of it. Still later movies would go back to saying that he drowned as a child and somehow came back to life.
Revealing the end of the first movie to be a dream seemed to open the door for future sequels to do the same. Part II ends with a long-haired Jason but Part III skips that and seems to retcon it into a dream as well. Then Part III ends with its own dream sequence.
This movie has a few scenes to recommend it but it doesn't add much to the series and makes a mess of the backstory.
Well, I certainly can't disagree with you about the chronology. It makes no sense. Honestly, that's why I barely touched on it.
What I like most about the first two movies is that I find them the scariest. Also, the first three have the most nostalgia value for me. But you are right about the problems.
Unfortunately, I've lost some of my videotapes over the years, so I probably won't be rewatching the entire series. I haven't seen 4, 7,8 or 9 in years.