Coming back to circuit #1: after removing the 0.1µF capacitor nothing (new) happended – it works in the same way as before.
And why not using (-) as GND – since 1953 the so-called GND changed with nearly every radio model / maker / whatever circuit. Always since that time PNP and NPN transistors (first Germanium, since ~ 1963 more and more Silicon types) were used in a mix (instead or as a compliment, for example push-push stages without transformers). Car radios had an external switch for changing (+) or (-) to car chassis GND.
So I used in a second experiment this variant – and needed 9 blocks less = > 24% (!)
The 0.1µF capacitor was not needed for the asked function, neither with the PNP Germanium (above right) and nor with the PNP Silicon transistor (inserted block).
With the second circuit (easier to understand like electronic dummies like me 😉 I will report soon.