Jane Darwell = Big Nose Kate?

Anybody know what's with Jane Darwell's role in the film? I waded through the DVD commentary, but he ignores her for the most part. But, what the heck was she doing there?

Part of me thinks that she was meant as a substitute for the "Big Nose Kate" character whose usually the love interest of Doc Holliday. Here, of course, that figure is a mix of Clementine and Chihuahua. Obviously there's no hint that she and the Fonda-character are 'involved' at all, since Darwell plays her usual maternal figure here ('young man you be careful!').

But, Darwell's character is named 'Kate,' is a saloon/boarding house owner, probably 'a Madam,' and kinda looked like 'Big Nose Kate' in her later years (the real Kate actually died in 1940, and was something of a local celebrity in the Tombstone area). Darwell's character doesn't get much screentime in the film, less than I thought she'd have gotten - but do I have something here? Was it some kind of homage?