Here is the more-or-less finished "Light Horse Harry" Lee. I have opted for a green jacket with brown facings, why?
There are no clear indications of what Lee's Legion wore. They were initially part of the 1st Continetal Light Dragoons which wore either brown coats with green facings OR blue coats with red facings OR both (either at the same time or at different stages of the war). Late in the war, or just after, the Legion are known to have worn buff uniforms with green facings. There are contemporary accounts of Lee's dragoons being gonfused with the cavalry of the British Legion and the Queen's Rangers and as both of these wore green coats I have opted to assume (without further evidence) that Lee may have reversed the colours of his original regiment and gone south with green coats faced brown, as shown, bofore again reversing later in the war - or perhaps the coats were reversible!
I'm happy with this approach, but I don't for a moment claim it is 100% accurate or expect anyone else to follow this colour scheme!
Other angles below: