I hunted Pelee Pheasant hunts for more years than I care to admit. Your questions are completely irrelevant to the success of your hunt. 700 licenses were always available for each hunt and 7000 birds where always released for each hunt. If they only sell say 600 licences 7000 pheasants are still released as there already planned for and they can't keep them over the winter.
In my experience the third hunt was the best to attend as the bean crops were always off the fields and there was more stray birds about from the previous two hunts that were not shot. The most important thing you require is a good dog, I can not stress this fact enough you must have a good dog. You may think that with 7000 ++ pheasants running around a small island it should be a barn yard chicken shoot but nothing is further from the truth. If you do not have a decent dog your not going to get anywhere near the birds you paid for. The only issue with the third hunt can be the weather can be a little nasty with high winds which affects the ferry.
I always hunted with labs and 3 of my labs spent a large part of there lives hunting pheasants on Pelee. Many years we did two hunts. The first morning is the big event in an attempt to get the most birds you can by noon Thursday. So you will be up very early sitting in your truck at your preferred spot absolutely no later than 6am preferably well before. The hunt starts at 0800 sharp. Try to get a long ditch line that you know from Wed eve scout hold birds. Stay the hell out the bush areas opening morning, there dangerous places to be, as you stand and excellent chance of getting shot or sprayed with it. There are birds, hunters and dogs going in all directions it is pandemonium at it's worst. Browns Line would be a good example of where not to be opening morning.
Your best to hunt in pairs with one or two dogs depending on what you have. You can then have a decent hunt in smaller often overlooked little areas. After many years we rarely needed to hunt the second day. On many a year we had all our 20 birds by noon Thursday. One year we had all 20 birds and back at the truck in 57 min. We were forced to wait until after lunch to clean birds and drink scotch. It takes one bottle of good single malt scotch for two fellas to clean 20 pheasants, at least that's the ratio we discovered.
Have an enjoyable safe trip.