[exsion]

If a TRRS balanced cable follows the L+ > R+ > L- > R- diagram. Would it be possible to plug it into a unbalanced output and have the last two negative share a common ground?

And following along a similar route, would a TTRS with a mic option that follows L > R > G > M also work in these sense of having the last two poles share a common ground?

 

[castleofargh]

bringing the 2 sides to a common ground is what happens in all single ended headphone cables. they all start with 2 wires on each side at the very least where the coils are. the variation here would simply be where the joining of 2 wires happens in the cable. so that's very fine. you'll have to solder something(but then the cable cannot be used with balanced gear anymore), or get an adapter/make one yourself.

for the option with a mic, I'm not sure I understand what you suggest?