I think we'll need better photos (and probably not via the app as they seem to be rather low resolution). It looks like a nicely decorated movement but I see it's missing the crown so it's a non-runner. This could be an easy thing to fix or it could be a complete money pit - that probably explains the variance in the offers you've had.
I haven't been tracking trench watch prices for a couple of years but I'm sure there are others here who have. We need better pictures.