The X will show in the finder if film is not loaded. Aperture and shutter speed are displayed when shooting in Program or "A" mode.
In manual mode, you see the shutter speed you have set, but not the aperture. The other number is your underexposure or overexposure based on what you've selected. -3.0 means you will be 3 stops underexposed, -0.5 means you are underexposing 1/2 a stop. +3 means you are overexposing by 3 stops. Just adjust your shutter speed or aperture until this reads 0.
The wheezing shutter sound is normal for RF645 bodies. That being said, I absolutely love mine ... the lenses are outstanding!