[1. ]Is it possible to program it with standard C++ or C?
I've found the C++ support to be excellent.
Bear in mind that, by default, there's no heap. For me, this hasn't been a problem but it can be a little confusing if this is your first work with a microcontroller.
[3. ]Can i program the board to take input, send it to the computer at the same time as i send two different signals to the board (multitasking)?
Even though there is no multitasking support, transferring data to the computer is driven by interrupts so it's essentially done in the background.
- Brian