Yeah weasels are nasty, vicious little things. Keeping your traps going and covering every little gap you can with hardware cloth is about as much as you can do. Good luck!
I'd agree those are raccoon tracks. I've trapped a couple this week and the prints I found were more or less identical. They will 100% go at the neck to get into the chest cavity. I've had luck using marshmallows and old eggs as bait.