I'll say no to all too.
1 I don't know much about moose, is the white seasonal or rare? Also, it looks young, maybe too young for a legit harvest. That shot looks like it's better to take with a camera than a firearm.
2&4 mother with young, just can't do it myself. If they were in my garden (I can't tell you how much my garden has suffered from the whitetail) I may feel differently. Maybe, maybe not. The question in the OP sets the stage as hunting with only a couple of days left to fill a tag. I couldn't do that to fill a tag. Again, good shots with the camera.
3 Even if it were a legal shot, which would depend on the state you were in when this shot presents itself, there is the probelm of retrieving your kill. That is a large animal. I wouldn't want to try to drag him out of there. I'd sit and wait and hope he got himself to a better spot and then consider my shot. Again, I don't know much about moose or moose hunting. Maybe these thoughts are way off base and the logistics of moving him are something that I would have a plan for before I was in the position to have to do it. Sitting here looking at the screen, I don't like the shot. Maybe others can weigh in and I may learn something.