SVN and II are two separate entities.
At your home resort you can make reservations between 12 and 8 months out from your arrival date. If you want to use another SVN resort (assuming you are part of SVN), you make your exchange between 8 and 0 months out. All this is independent of II. SVN membership is mandatory for some resorts and voluntary for others. SVN membership does not transfer with a resale purchase at a voluntary resort.
If you decide you want to get an II resort, you can start trying 12 as long as you have a week to deposit. This is independent of SVN. You can do a "request first" where a match has to be found before your week is deposited, or you can just deposit a week and you have up to 2 years from the date of the week that is deposited to find a new place to go through II. You do the former if you know what you want, the latter if you are running out of time and have to deposit a week without plans on where you want to go. In any case, Starwood gets to choose what week they'll deposit. If you wait until the end of the year they might only have say an April week to give you (that they previously deposited) so you don't quite get 24 months to decide where to go. This happened to me.
II has nothing to do with whether you'll get to go to St. John through an SVN exchange. As a matter of fact, I doubt II will ever see a Maui or St. John week deposited since Starwood would likely put in a week at a different resort.
As to your questions:
1.) I've tried to exchange WKOR to St. John in the summer months and have not been successful. I hear if you wait long enough you might luck out, but I ended up using my weeks in Maui rather than risk not getting something in St. John. My issue was more with getting decent airline connections than with just being impatient. Perhaps other seasons are easier to get.
2.) You can attempt to exchange as soon as your arrival date at the other resort is less than 8 months out.
3.) Mainly flexibility and patience. If you have many different weeks you can go, there's more likelihood you'll find something. If you are 4 or 5 star elite, then you can always reserve at your home resort and be placed on a waiting list at St. John. That way, if it doesn't come through, you still have a desirable Maui week to use.
4.) I am not sure about the view question. Do be aware that your priority for a unit is below that of home resort owners, Elite owners and maybe even paying guests. I've heard quite a few exchangers into Maui complain about getting poor views. If the resort is full you will likely not get a good view. I have no idea what the view situation is in St./ John. Maybe it doesn't matter there.
For St. John it might be best to find someone to exchange with directly. This is also hard to do but if you can even the playing field a little, say by offering a 2 BR Maui for 2 BR St. John (St. John is worth fewer StarOptions), you might get more interest. I'm still looking for that elusive exchange myself, though.
Henry