FWIW, I had a similar list of deteriorating rubber bits on the ST2 I purchased almost a year ago, and I bought replacements from StarTwin in Holland. I've since placed further orders with them for my wife's MV Agusta, and found them to be excellent. No connection etc, YMMV etc ☺
You can get much of this stuff from the dealer for less than you might think. They may charge $18.00 for a fuel flange o ring you can get for $1.00 on your own, but I have purchased lots of rubber pieces over the years for very painless amounts of money. Certainly the parts are still expensive for what they must have cost Ducati, but they are items you really cannot get anywhere else. Sometimes it takes a few weeks to get something, but it has been rare I've been unable to get an odd rubber replacement part from the dealer.
Some examples. I was able to enter the number and get a price, that normally means you can still get the part. If an item is no longer available to order, it will say so. One time, for a 1995 916 part, I was able to place the order, but got an email later on telling me they couldn't get the part. No problems, I found one on eBay.
Rubber bush for the exhaust hangers: 76410011A Minimum order of two $2.99