Would like to know how the filter wizard does this calculation. It's obvious that the opamp's en and johnson resistor noise are components but would like to see how they combine. How does each stage contribute? Can I reverse stages? Seems like, for example, for a 3rd order low pass that the first stage might be either the second order one or the first order and how does this affect the noise calculation?
Also, why aren't my favorite opamps in your selection table: LT1028 and LT6018 (low noise btw)?