1) Yes. It is normal Ubuntu. You'd have to install some extra packages. 2) Yes, you can execute code in Desktop or Mobile - how you deliver the interface though

1) Yes. It is normal Ubuntu. You'd have to install some extra packages. 2) Yes, you can execute code in Desktop or Mobile - how you deliver the interface though would probably be done by either HTML or C++/QT Quick. 3) Yes, yes and yes. 4) It is a single environment with multiple interfaces. Plug it into a monitor and Unity Next will switch layout to Desktop - Plug it into a TV and it'll switch layout to Ubuntu for TV. All the underlying code is the same.