Consulting some questions about amplifier

1.For bipolar amplifier, we consider the output impendance is resistive, it is not variable with frequency, is it true? But for CMOS or JFET amplifier,the output impendance is changed with frequency,yes or not?

2.Are all the amplifiers a single pole system?

3.we know that slew rate limits bandwidth, Fmax = (Slew Rate)/2πVpk，we get the formula from sinewave input signal, but for other input signals,such as square,triangle and arbitrary signal and so on, what's the relationship between slew rate and the full power bandwidth,Fmax?

Thanks!