Some of you seem to be crediting Edward with cold reading abilities that almost equals psychic powers (no I’m not saying you are believers so keep your dummy in).
That would only be the case if he did this every night. If he does this once in a blue moon then we are crediting Edwards with being someone who does this for a living and is probably quite good at it and for whom a long shot occasionally pays off.
If anyone seriously believes Edward could have cold read Liam given the circumstances RemieV has given (below) then you have no practical cold reading experience or knowledge. It’s not as easy as some seem to think even when circumstances are more favourable.
When you talk about the cold reading, are you referring to the fact that Edwards knew that Joshua was Liams name but did not introduce himself that way? Or are you referring to the reading that, according to RemieV, happened after that?
If you are referring to the subsequent reading then we don't have enough facts about that to know how good it was.
If you are referring to his identifying that Joshua was his name, but not the name he gave to the table then I agree that it was most likely that Edwards had that information in advance, although I would probably need more information to be sure.
Cold reading is hard, but Edwards doesn't get something this impressive every night and sometimes he goes out on a limb and gets flattened.
I remember that once he suggested described a very specific event about someone's pet and when this fell flat he quickly said "Oh, I see, it hasn't happened yet".
It could be that once in every few hundred times going out on a limb like this pays off and it is apparently no big deal when it doesn't and very impressive if it does.
How do we know that Edwards was pointing at that particular table?
He points at a particular direction in the auditorium and says "Joshua" and someone stands up. Presumably there was more than one table in that general direction. We are crediting RemieV with pretty good eyesight too if we say she can be certain that he was pointing at a particular table sixty feet away.
Did Edwards actually mentioned the name "Liam"? That part is unclear. As I read it, he said something like "I have the impression that Joshua is your name but you didn't introduce yourself that way", not mentioning the name "Liam" at all.
Now I am looking at someone about 60 feet away at the moment and I think I could probably read their expressions and body language fairly well. And performers who involve the audience don't normally work with darkened auditoriums and lights in their eyes.
I have set up a few stages and it is quite easy to correctly light someone without dazzling them.
So he could have taken a longshot and if it had not paid off and it had turned out to be a dead relative or friend then Edwards would have said something like "Wow, you two must have been very close for you to be so closely identified with him!".
All that said, I think that it much more likely that he found or came across the information earlier.
The only question that remains is from what of many possible means did he get it?
And at this stage not a particularly interesting question, given that there are many ways he could have gotten it.