Should I think of "would have pp" as speculation about the past or 3rd conditional?

1. Snape examined Goyle, whose face now resembled something that would have been at home in a book on poisonous fungi.

2. Robert Baratheon and his brothers were all big men, as was the Hound, and back at Winterfell there was a simpleminded stableboy named Hodor who dwarfed them all, but the knight they called the Mountain That Rides would have towered over Hodor.

Hi. Dear teachers. Last year I asked a similar question on "would have".

Mr. CJ had taught me that when it comes to "would have pp", I should think the "would have pp" is not subjunctive but only serves as an just speculation/supposition of possibilities of some event in the past. Now I read that thread again and have another question. In that thread, I have produced four example sentences from novels and Mr. CJ also told me they were all 3rd conditionals.

This is the link:

Now my question is: when I come across "would have pp" in reading books(not limited to novels), should I treat all of instances using the pattern "would have pp" as speculation/supposition, or should I treat them as 3rd conditionals? As in the two example I give above. They are speculations? Or 3rd conditionals?

I asked it because 3rd conditionals and speculations seem at odds with each other. The former is counter factual while the latter is non-factual. So they are different. And Mr. CJ told me usually there were if-clauses lurking behind "would have pp". So does that mean all "would have pp" are 3rd conditionals? If so, how come they are speculation at the same time?

Thank you very much.