Funny, it looks like we're trying to do the exact same thing animation-wise, though your setup looks to be more state-driven :)
I have all the same locomotion (my 'running land' doesn't flip' but it is unique from a stationary land) but I found this thread while trying to implement crouching and crawling.
I see you are manually resize your player object but wouldn't it be a more flexible system if you were to make your crouch values a percentage of the original, standing size? The 'scale' property is looking for a percentage but height and width are looking for integers.
I've searched around a bit but haven't been able to find an expression to set height or width to a percentage of their original. Any takers?