I know you are looking for input on your 3 season list, but I chose to look at it in the context of your planned trip. Isle Royale is an awesome place!
In late spring/early summer you will still have some mosquitos hanging around. Depending on the temps in the spring they shouldn't be too heavy, but they will make their presence known. Do you have any kind of bug protection? I don't believe that the Grand Trunk hammock has a bugnet, and I don't see even a headnet on your list ...
I've had weeks up there that were perfect weather, but also weeks where it rained 5 days out of 7. You have some good raingear on your list, but plan on how to keep your clothing dry (especially the down jacket) as it probably part of your sleep system with that light a sleeping bag. During the first week of July I've experienced 20 hour thunderstorms and the temperature dropping to about 36 degF. I've also seen nights in the 60s, so there is a huge amount of variation!
Are you taking any spare socks, or will your sleeping socks do double duty? If the forcast is for rain you may want to reserve a dry pair for sleeping.
What clothing are you planning on wearing? If you are carrying the clothes on this list you might be able to do without the shorts?
What boots/shoes are you planning on using? Much of the terrain is rocky so a good sole is important.
That pad should be fine in a hammock, but there are shelters available at some of the campsites. It may be a bit spartan if you stay in a shelter instead of hanging.
As has already been mentioned, water should be boiled or filtered. Boiling adds fuel weight and extra work; it works out lighter to add a couple ounce Sawyer filter with a sipper tube to drink thru or use as a gravity filter?
I don't see a pack on your list? Were you planning on doing a bedroll and using the hanging suspension? That would be cool, but maybe not so convenient for accessing items on the trail.
The Trails Illustrated map of Isle Royale would be good to have alongside the compass. A compass may not be needed if you are staying on-trail.
I'm not familiar with that cookset, but I assume it has a spoon or spork included in the weight. Also a windscreen? 8 ounces seems heavy for a kit using a Heiny pot, unless maybe it also includes fuel?
Food weight may be easy to trim down at Isle Royale, depending on your route. Points of entry are at Wendigo in the west, and Rock Harbor in the east. During the time you are planning, food is available at both these locations. You can purchase sandwichs and camping food at Wendigo, and there is a small restaruant and grill at Rock Harbor as well as a small store with food. If your route is end-to-end you can resupply at the far end if you aren't too picky about selection, and if you are spending a night at either end you can purchase meals rather than carry food.