1). Not sure, I think that's not too bad.
2). The mudflap in the rear actually will just unbolt, unlike the 929 where you had to cut it off. There area few options for a license plate hanger, Harris being one of them. A seach will yield what others have used. Several good options.
3). Most folks here prefer the Scotts Rotary Damper. I personally like the piston style and I have a HyperPro. Were I to do it again, I'd probably go with the piston-style Ohlins. There's other good ones too: Matris, Storz, to name a couple. The general consensus is that the 954 needs a damper. They are very light steering and have a lot of horsepower, so headshake isn't uncommon. If you search, you'll see differing opinions. It's probably one of the most argued about points on the forum, next to what oil to use.
Personally, I think it's good insurance, especially if you ride somewhat hard or plan to do trackdays. Most of the ones I mentioned are bolt ons. No drilling needed, I'm not sure about the Matris or Storz, but the others are bolt on.
4). I have Intuitive frame sliders. No cutting needed. Whatever ones you get, read the directions carefully. There is one side with a longer bolt, and you can't mix them up or you'll screw right into the engine. Other than that, it's a simple install.
Dan Kyle, a sponsor of the site (see a link on the site) sells everything you could need/want and more!
Edit: bwhip is selling a Scotts damper for the 954 at a good price, look for his thread...