Bushy tree had the 1-pixel outer lines adjusted, then I painted over the rest with a thick brush; you can tell by the grainy, pillowy effect.
The barren tree was too crushed up from the upscaling process because of the curved lines; I had to redraw it completely. No ambiguity there.
The wide tree was edited a little more carefully because of how small the leaves were; I had to go down it chunk-by-chunk to redraw the edges of each spot of colour, like I would with lineart. This is the 2 day tree. It is more or less "drawing over" the image, but it was all done on the same layer, simply because of how pixel art works. I don't really have any way of knowing how much was "my" work in that case. Judging from the fact every leaf was originally a perfect rectangle, presumably more than 80% is my work, but.... ????
Similar problem of ambiguity with this white bridge: the "lineart" was redrawn, but the noise was copy-pasted from the original because I had no idea how to reproduce that coloured grain, and then edited those pastes so it would fit on the boards.