Ultegra, Dura-Ace, and 105 10-speed shifters will all work. You don't have to get a 105 cassette.

The deal with the chainrings is that the spacing between them and width of the chain is different. A 10-speed chain can (potentially) slip down in between the chainrings and lock the crank, but IMHO this isn't really much of a possibility if everything is set up correctly and you're not cross-shifting all the time. If you're super worried about that, you could even just file down the spacers between the rings to get the narrower 10-speed spacing with a 9-speed chainring set.