Impact of "reference level" and "RBW" on the time domain signal in spectrum analyzer?
(1) No. Reference level is the y-axis of the spectrum display of a time domain signal. Modifying it does not change the spectral shape, it just moves the display up/down. (It also sets the input attenuation which affects the displayed noise level)
(2) No. RBW does change the spectrum display, as it is the measurement bandwidth (kind of a frequency mask) that is applied to the spectrum display.
Addition: VBW smoothens the spectrum on the display (it is kind of a display filter).