I personally have little experience bikepacking, but do have experience backpacking and bike commuting in the rain.  I like my Marmot Precip-fairly light, and not too pricey, but has pit zips, pockets, etc. 

Not a big enough hood for a helmet, thought.  You are probably looking at a mountaineering jacket at that point.  But...have you ever ridden with a hood over your helmet?  In my experience, it becomes a spigot straight from the outdoors to your core because of forward movement.

No unless you get the stem plate version from JTEK, but then you may run into running too stretched out.  http://jtekengineering.com/jtek_Axe_aerobar.htm

I will start by stating that I never ride with a backpack on my back.  This past weekend, I decided to try out bikepacking, with stuff strapped on my handlebars (didn't lose hand positions on a standard drip bar, 44cm wide), a rear rack for my sleeping bag, and carrying some on my back (15 lbs?).  My  lower back and butt did not like the weight.  I'm assuming your 8lb kit does not include food & water, so at times your backpack's weigh will increase significantly for a short time.  Of course, different people have different tolerances, so I think it's a great idea to do a few shakedown rides of mileage/roughness/time comparable to a normal day on your tour.

If you go to the transwi site, there is a preliminary map embedded from everytrail http://www.everytrail.com/view_trip.php?trip_id=1019282.  I just overlaid it on last year's route, and it looks like this year's start to Lake Superior are pretty similar.  I plan on riding part of it this weekend-maybe Cable to the lake and back (Friday and Saturday), then ride some of the CAMBA trails on Sunday (opening day).

I've been lurking long enough that I figure I should introduce myself.  My name is Andrew.  I am fotooutdoors on forums.  I've spent a good portion of time wilderness canoeing, some backpacking, some bike touring, a bit of mountain biking and a ton of day hiking.

I love going somewhere by my own power, and not just in a loop (though those are fun as well), which is why bikepacking intrests me.  Plus, I just love being outside.

Currently, I live in Madison WI, which isn't amazing for getting out into wild areas.  I'm drawn west (worked at a camp on the Pikes Peak Massif for a summer and loved it), but both my wife's and my family are out east...time will tell where we end up.  Right now I'm mainly dreaming about bikepacking, but I hope to spend some time in the north of the state this year in addition to road-based bike trips and day mountain biking.

Will you be carrying a cell phone?  When traveling, that's my alarm clock.