Looks like the daytime temperature range for Hawaii is around the 80s in the summer and the 70s in winter with nights about 10 degrees cooler than days. Your 40-degree bag might be too much. I find that when it is hot it is hard to sleep without at least something draped over me. I've had the experience of being in the desert and having it so hot I couldn't cover my body but I could feel bugs landing on my legs and with nothing covering me at all, looking up at the night sky and feeling like I could fall off the earth without anything to hold me down. A thin sheet would have been nice. Probably your fleece insert would be enough and you could always buy a blanket or something from a thrift store if it wasn't enough. This is all a guess, never having actually been to Hawaii. It's possible it might get cold, especially at altitude or in a rain storm.
Female, 5'3", 50, Max squat: 202.5lbs. Max deadlift: 225 x 3.