CDO

I am doing statistical downscaling of precipitation and temperature.I am new to the netcdf file format and climate change as i am a water resources engineering student.i am having following doubts about CDO.

1.Can I use remapbil to extrapolate data of a .nc file at various pressure levels?

2..My NCEP data is on global lon lat grids at various pressure levels at a resolution of 2.5 x 2.5 degrees and GCM data is at a resolution of 2.5x1.85 degree.Can I use remapbil to do horizontal interpolation at all pressure levels simultaneously from GCM (2.5x1.85) to NCEP (2.5x2.5).

3.The variables I am using are 1.Specific humidity at various pressure levels, 2.U-wind at various pressure levels 3.V wind at various pressure levels 4.Surface air temperature 5.air temperature at various levels 6.sea level pressure.my question is can i use same cdo operator remapbil to interpolate all variable.(Because, in NCL functions, they have different functions for diggerent variables that is for scalars and vectors seperately).