For the bullhorns, your bike sits on 26s, so these will work:
http://www.amazon.com/Origin8-BullHo...=25.4+bullhorn
The 25.4s will work as well, but may require a shim to bring it up.
And the brakes, I am unsure of because it does not show the diameter measurement. If you get that bullhorn, I suggested, you should be able to fit 24mm brake levers on there.