Output Key Figure (which means in display mode only)
Input/Output in specific period (which means editable in specific period)
The first two could be achieved while designing planning book itself. If you right click on the key figure we have option of selected rows where we can select output only or input/output (though by default its this).
For third situation we can use macro i.e. Input/Output in specific period by using LAYOUTVARIABLE_SET, LAYOUTVAR_VALUE & CELL_INPUT function. In the below example specific key figure would be available for editing from 11th to 18th every month. Otherwise it will be in display mode only.