Ken, these are all good questions!
Trekking pole straps–yes, I use them. That way the pressure is on my wrist and the heel of my hand, I don't have to grip the pole hard with my hand and I have no problems with my carpal tunnel syndrome. Using the straps also means I can snap a photo and/or manage my dog's leash without having to drop the poles. For how to use your straps, see:
http://www.personal.dundee.ac.uk/~pjclinch/poles2.htm
Dirty laundry: I rinse socks daily. Otherwise I'm wearing it and it waits until I get home. The general rule for lightweight backpacking is to take only the clothing you would wear all at one time in the worst conditions you'd expect for the specific trip, the exception being a spare pair of socks. The time I slipped and fell in a big mud puddle on Washington's Olympic Coast, I wore my base layer top and rain pants while rinsing out my very muddy pants and shirt (in that case, in the surf). I wear quick drying fabrics so they were almost dry in an hour even in the coastal damp. I put the damp shirt and pants back on and my body heat finished the drying in another 20 minutes. A gallon ziplock bag makes a great "washing machine" for socks and lets me dump the dirty water 200 feet from water sources. I also use that bag if my clothes or socks are damp at bedtime–I seal them in the bag and put it inside my sleeping bag. (I wear my base layer for sleeping.) The clothes aren't dry in the morning, but at least they are warm when I put them on, and no moisture gets into my sleeping bag insulation.
Garbage: I use the freezer bag "cooking" (really rehydration) method, so I have a dirty quart ziplock bag every day in which to seal garbage. At the end of an 8-9 day trip, I may have at most 2 or 3 quart bags full–and that includes TP and the bulky pads this old lady is obliged to wear. It easily fits into my bear canister or Ursack. If your garbage amounts to more bulk or weight than the food you packed in, you're most definitely doing something wrong!
You mentioned a mid-trip resupply; if you're having somone come in to meet you, he can easily take out a sealed quart or two of garbage. IF it is legal to build a fire and there's an existing fire ring (note that the existence of a fire ring doesn't necesssarily mean a fire is legal!), you can burn at least the bulky garbage; just don't try to burn thick plastic or any aluminum foil. Don't do this close to your camp, though, since the odor of burning food may attract wildlife. I rarely build fires but just pack everything out. I also pack out trash "found" along the way if I possibly can.
As for the TP: my "lunch" (really a continual moveable feast of snacks) for each day is packed in a zippered sandwich bag, so at the end of each day I always have a sandwich bag available in which to seal the next day's TP. That bag is sealed inside the used quart freezer bag from my evening meal, which amounts to double-bagging the TP. That's sufficient to avoid contaminating my food! If there's any smell, neither I nor my dog can detect it.
I know that some folks like to burn their TP. I also know of a number of forest fires that have started that way! If it's dry and windy, or your cathole is in dry organic soil, please don't try! If conditions are wet, you can bury the TP in the cathole, but soak it thoroughly so it will disintegrate faster. If the soil is dry, though, please pack the TP out!
There's an amusing book available called "How to S*** in the Woods," which should be required reading for everyone going out into the wilds, even for half a day!