The answer to each of your questions is essential yes, but there are details to be aware of. Windows systems require more space to display the same text with the same size and font as on mac. Since your want to develop on Windows, but use on Mac, you'll have less issues with this than the reverse, but always check your layouts on both systems to make sure they work for both. It is sometimes necessary to create layouts for both platforms and then use a script that detects the current user's operating system in order to select the correct layout--usually you don't have to do this unless you have a layout where there is very little room for everything. Also double check the differences in screen size and resolution to make sure your layouts work acceptably with all of the different ones your users may have.
There is a very short list of features that are either mac only or windows only or which produces significant behavior differences. (New window and Insert Object come to mind here.) So this is another reason to test your solution from time to time on the other platform to make sure you haven't set something up that doesn't work well with the other system.
Finally, your chinese users will be able to open and use your file and if they have installed the chinese language version, they'll be able to see menus and built in dialogs in this languabe, but anything you have designed, such as a custom dialog or text on a layout, will still be in English. If this is an issue, there are ways to set up layouts so that the text in them is selected from a list determined by the user's language preference, but this is something you have to develop and put in place--it's not built in for you.