Too far down the road of downgrading?
loading second stage down with resistors, loop gain went from 65dB to 25dB, thd will increase by more than an order of magnitude. No idea how much would be the sweet spot subjectively but can possibly be further tweaked.
FET output, linearity not as good as triple BJT, just bc still try to cut corner on size...
A quick search suggest lateral FET pretty much went extinct, for vertical ones should probably change vbe multiplier to something TO-126 and also put on heatsink?