If they just walk in on Tyrael while he's in the forge, likely next to nothing unless they're familiar with Tidehome. Otherwise they'd know at least what Tyrael said in my last post. 

If you mean what do they know about the Hunt itself, well Tyrael was asking around for students who had some free time, and if they did they were to find him. So if you want to have a reason for how your characters know to look for Tyrael there's that; they heard he was looking for students and so they are there to figure out what's up. Once you get a post done for those two I'll see about getting one for Tyrael and the Caravan Mission.