RTOS/cc2650: Task variable scope, stack size, and other questions

Part Number:cc2650

Tool/software:TI-RTOS

Hello,

1. When creating a task within the cc2650, there is the option of giving it a stack size in what is documented as "MAU" (Memory allocation unit). How many bytes is a memory allocation unit? I'm assuming it is 1 byte but I am unsure.
2. When creating two or more simultaneously running tasks within the cc2650, do all tasks share variables declared within their own local scope?
3. Since each task has an allocated stack size, I assume there is a maximum allocation for the entire stack. What is the maximum stack size?
4. When using malloc() within the cc2650, I will assume that the memory is allocated to the heap. How can I know how much data I can allocate to the heap?

Thank you