For Qui-Gon, I could see him in grey robes, maybe to reflect his more maverick views on the Force within the Jedi Order.

But I think you could keep them as-is too. Maybe having the rest of the Jedi wear more elaborate robes, whereas Qui-Gon wears very simple robes, would be a good way to separate his character from the rest of the Jedi.

EDIT: Alternatively, if Luke’s ROTJ is meant to be the Jedi uniform, having Qui-Gon wear grey with black underneath could go along with that idea.

I think the battle droid color scheme was meant to evoke the color of bone, since they have a skeletal-like frame, but I have to agree I would like to see them with a more metallic, industrial color.