That's good advice about the racks.
My advice considering your weight, but also just what happens touring, is to go with double brakes. I mean your whole life is pretty much hanging by a tiny piece of aircraft cable and a nut. We are not talking swaged climbing gear, but the kind of thing that can rattle loose. So I would go with V or canti, and a disc on the front. On the back just a regular V or canti. You need an extra lever, up top which is comon with those cyclocross levers, so why not a small lever up there. This is on my to-do list. Though this is unconventional, I think it is important. The only problem for touring is you get a dished front wheel, and different length spokes due to the disc mounting. But MTBs hold up to the thrashing so it shouldn't be a problem. Carrying all those spokes is a bit of a bummer though.
With the hubs, you should spend the extra money for a heat treated axle. That leaves you with Phils and DT Hugli, and a few others. I would go to the Hugli, because they are stronger and cheaper and have a lot of options for disc drag brakes, 135, 145. I would look into 40 or 48 spokes and Velocity rims, rather than just hoping something called rhyno is right for you. Think positive, you are now all about velocity not rhynonis (I'm trying too). More spokes is probably better for you and a deep rim, than the merely heavier Rhyno, and now that it's been lightened... The only bad thing about Huglis, by the way, is no sealed bearing, I believe. But that is not a real problem in most cases, My truck doesn't have sealed bearing and it sees a lot more road salt etc... than my bike. If you are going underwater, then maybe. But these things are designed for MTB use, and most touring is not so hard on seals.