Good work! Just to clarify, these are the TFs for the output immediately at the output of the low pass stage of the circuit?  A diagram, even a hand drawn one, is a good idea so people three years from now can know what you were talking about. Also PDFs are probably best format for plots as they embed vector graphics that can be zoomed in, I often also like to attach data in a zip with plotting scripts so people can quickly replot for themselves.

I find it strange that the corner frequency is so high for the choices of R and C.  It should be much lower f = 1/2piRC= .159 Hz for R = 100 kΩ and C = 10µF.