Wow, that's quite a variety of topics you've brought up. Not trying to be rude or anything, but have you browsed any good gear stores (and/or online sites) to get a feel for the options available? If so, were there any products you liked, but aren't sure if it's exactly what you want? If not, here's a good place to start:
Recreational Equipment Incorporated (REI):http://www.rei.com/
For example, you mentioned that you're looking for a lightweight tent. You can browse REI's selection of Tents and Shelters
and then narrow this search down to one-person tents and weight categories. However, keep in mind that the "lightest, breeziest one-man tent" available may not be a good tent at all! Personally, I usually decide to sacrifice saving some weight in order to get a more durable, better quality product.
For handlebar bags, I have the Ortlib Ultimate5 Plus
. Matches my panniers and just looks awesome. Plus, it can hold up to 3 kg (105 oz). There may be handlebar bags out there with more features and that can hold more weight, but it's not really a good idea to have much weight above the wheels, anyway.
Don't know about mitts or front fork water bottle cages, but hopefully I've given you some leads to get started. Good luck!