Will Unity be considered as interface for Kubuntu?

The Kubuntu team has a wide degree of freedom in how they structure Kubuntu - which apps they include and how they configure it by default. I doubt they will embrace Unity immediately, unless it proves extremely popular amongst Kubuntu users.

That said, we have done a lot of work to ensure that many key aspects of the interface and API's work across both GNOME and KDE. Menu's, indicators, notifications and lots of other goodness have been built for both GTK and Qt apps and are tested across both Ubuntu and Kubuntu. So Unity should work very nicely as the shell for Kubuntu if you want that yourself or if the Kubuntu folks decide to go that route.

I don't think so. If you don't like KDE interface, just use Ubuntu with Unity and install the KDE applications you like. Personally, I don't even know why that should be considered? I haven't tested Unity yet, but it looks like an improved Gnome-Shell, which was the main reason I switched to KDE. Besides, Unity is an Ubuntu project and Kubuntu is mostly maintained by the community.

If they change Kubuntu so much in order to use Unity I would probably move to a different distro.