For example, the File Manager and others softwares in development.
They should have similar look, but with more screen space and mouse+keyboard inputs it would be better to make slight changes to make better use of those. Take the File Manager for example, on a desktop with more screen space it will show the Places list in a side panel, while on a phone the Places are accessed via a popup from a toolbar button.
I believe so. As they exist currently you can easily run all of these programs on your desktop and play around with them. The way they look on your desktop is how they appear on the phone.
These apps are being developed for the phone however and will therefore not be ideal for use in a desktop environment.