I know it's a bit early, Windows 10 still being in Alpha, but hey, someone might know, and if not, I can always revive the thread in a few months.

Anyway. On to the question.

Does Windows 10 in keyboard-and-mouse mode have fullscreen apps like 8 or just windowed apps like 7? As, while windowed is certainly more practical for some things, others are awesome in fullscreen (e.g. Chrome in Windows 8 mode, which can then use a ChromeOS UI which is awesome for web browsing).

pretty much all apps can be made full screen if the developer wants to allow it. Heck you can enable http://www.engadget.com/2014/09/03/chrome-windows-7-desktop-mode/

F11 is a common keyboard shortcut for making an application go full-screen mode, and has been the case for a decade or so now.

I know about F11, but that doesn't really have the same effect as Win8 mode or similar.

As to the first half, great, now I can definitely upgrade to Win10 a few months after its release.