We want to cook them tonight but can't risk getting sick.
Yes! They will be fine..
not safe to leave meat to thaw out. I would say you should not use meat. Throw it.
It's impossible to say. While they were frozen for a good many hours, they also were in the temperature danger zone for a good many hours. As you can see by the two conflicting answers, there will be different opinions, but that's what they are..opinions. The health department would say toss them. I defrost certain things for a few hours on my counter, but then put them back in my fridge to complete defrosting. I'm fairly brave, but with that length of time at room temperature, I'd toss them.
Meat will generally tell you in no uncertain terms if it's gone bad- give it a sniff. Assuming you're going to cook it, should be no problem.
Here's where I use the phrase taught to us in Home Ec back in the 60's. "When in doubt, throw it out!" I've done the same thing and give it a sniff and feel it to see if it's gotten too warm. Which means it more than likely gets tossed.