As for (1) and (3), these are the ones I found most legible in both light and dark themes from the options I tried.
I don't disagree that 3 is practical, I just do not like it. And therein is the problem with colours, two of us can't agree, whats going to happen with ALL the Geany users involved :smile: Agree more orange than brown might be better.
For 4 I use a similar colour but less saturated, its not pretty, its sort of strawberry milk shake, but visible and obviously reddish for error, but probably not suitable for a default colour.