A:AnswerYou just have to be sure that the USB Unified symbol is on all your devices then they all work with one dongle! I had an older model that didn't have the unifying symbol and that one didn't work with the Trackball so I had to get another keyboard that had the symbol and all is well. I have a mouse and a trackball at work going through one Unified dongle and they work great as well.
A:AnswerYes, you will just need to adjust the modifier keys in system preferences to switch around your command and option keys, or just adjust to them being reversed.