Yes.
It it based on a spreadsheet implementation of a model in a National Semi databook. But with more frequency data points, and with amplifier noise taken into account.
And yes, you can always parallel opamps, summing their outputs via 10 ohm resistors. But even a single NE5534A is less than 2.5dB worse than the SNR with a noiseless amp (which is -80.4dB - depending on cartridge R and L) - so it is diminishing return. Parallel two NE5534A and you get to 1.6dB - so all you have found is 0.7dB in SNR. Parallel 4 and you find another 0.4dB and hence get to around 1dB of a noiseless amp.