3. Sleeping Pad (Purchased) - Depending on your budget... Thermarest NeoAir (nice, but $$$) or Thermarest Prolite Plus (nice enough)
4. Sleeping Bag (may need new one depending on total weight of the rest of items) - The North Face Cat's Meow is a very nice bag if you like synthetic
5. Camp stove (looking at the MSR Pocket Rocket) - The Pocket Rocket is a nice stove. That said I usually use a home made pepsi can alcohol stove because fuel is much easier to find in much of the US. That may not be an issue for you though depending on where you plan to tour in the future.
13. Jacket - I usually just take a pile sweater and use the rain jacket over it if it is cold. Lately I have started taking a down vest that is used mostly as a pillow, but if it is unexpectedly cold... I think I paid something like $30 for it from Cabelas.
16. Rain Gear - I like the cheapish coated nylon ones that come in a little stuff sack. I think mine is Sierra Designs.
21. Camp/Backpack Axe - Seriously? That is one item that I have never even considered.
24. Laundry Detergent for clothes - I usually take only one kind of soap and use it for body, dishes, and laundry. I have used on different trips, camp suds, dr bronners, and baby shampoo. All worked OK.
25. Chamois Creme - Never felt the to take this need myself.
26. Small soft sided cooler for grocery runs - Personally I'd skip this one.
27. 4 Water bottles - I typically take two on the frame and where necessary carry additional water in recycled gatorade bottles in the pannier. I just stop and fill the bike bottles once in a while. Be aware that some of the pumps on the C&O have absolutely awful tasting water and others are OK.