These Kahl drawings represent Robin Hood's earlier version based on Ken Anderson sketches.
Robin looks like a mischievous character actor, not the leading man type he turned out to be in the final version of the film. This is a more juvenile appearance with a skinny neck.
My guess is that Milt made these drawings to aid John Lounsbery, who originally was assigned to the lead fox character.
Fantastic sketches as usual by the one and only Milt Kahl.
A few of these drawings have been posted here before, but these images are scans from originals, not xeroxes.
I have posted numerous Robin Hood visuals over the years. My favorite post remains this bizarre interview with Milt when he was promoting Robin Hood in Dallas: