Mr. Vogel is the or one of the best guides on that river. Water is cold due to Lake Superior flows into the rapids, I have never fished but read a lot about it. Breathables should be OK, heck its the summer time. Bring both if your worried, I always bring two pairs of waders on each trip, on breatheable and the neopremes. Wading in the rapids is suppose to be dangerous, very slick rocks and fast water, caddis, mayfly, and stone fly nymph patterns appear to be the hot flies there. Also would have some smelt patterns.
Good luck, let me know how you like the rapids, been on my to do list for 10 years but those other blue ribbon michigan rivers which are closer to me always get in my way, along with my sons sports schedules and business.