Hi Jon, is this taken on the same day as the previous one on your workshop, or another day?
I can see you were struggling for light, shooting wide open, based on ISO 8000 and a SS 1/320 HH, so I'm guessing NR was quite high based on the previous Raw. I quite like the low POV, lower would be better but I know you said it was difficult to do so. In terms of capture I much prefer this with the beaver heading towards you with the vegetation in the jaws. Good call if you have darkened the FG just helps the image. Personally I'm not loving the framing, perhaps less above and a fraction off the RHS just to take the subject off centre, but still giving space in the FG for the Beaver to swim into.
Colour I think you are getting there, it is overall a bit OFF still, however we are looking at your 'processed' file, so its obviously taking in you tweaks, adjustments and manipulations. The boulder and grey 'branch?' on the RHS I would evict, they just catch my eye and when removed the image looks cleaner, but ultimately there is noting conflicting with subject.
One thing you should perhaps look into, Canon has always had a slight magenta bias, Nikon is Green, so it may help if you could see if the raw file from the OM system has a slight cast to it at the start.
TFS
Steve