how did Saruman
know that the dwarves were coming to Rivendell - and enough in advance that he had time to get there and make a fuss about it? It's quite a trip from Isengard to Rivendell, and he wasn't usually a roamer. The dwarves *may* have been there a while by the time he arrived, but Elrond didn't seem sure what their quest was until he read their map, and by that time Saruman was already there and upset, based on Elrond's comment to Gandalf. So just what did Saruman hear, and from whom, that sent him up to Rivendell in a temper?
It's possible that Saruman was watching Gandalf via palantir and that's why he knew things he hadn't been told. They might be beginning the "traitor" setup already, but it would be a little early for the orc connection, as I've always thought Saruman's breeding program didn't start until he came under the influence of Sauron - and that would have been after Sauron set up in Mordor, I think. (Am I wrong? Do we have any solid dates for when Saruman turned?)
Azog has clearly sent word throughout orcdom that he is after Thorin, because the Goblin King tells Thorin he knows someone who is looking for him and then sends word. But the question is, who told Azog where to find Thorin? It's possible that it's TraitorSaruman who set Azog on their track, but if it wasn't, clearly somebody somewhere was talking about Thorin's quest to the wrong people.
Let's see, non-Saruman options....it isn't likely that Gandalf had told anyone that he was getting involved with Thorin's obsession, but someone might have seen them meeting and talking together before he started searching for a Thief to make the Lucky 14. Suspect #1: Somebody at the Prancing Pony in Bree. This would be a possible Saruman connection too, if someone there (a Bill Ferny or half-orc type) was in his pay as an informant.
Thorin was also meeting with all his kin, trying to convince them to join him on his quest, but the only one mentioned by name is Dain. Is there a spy among Dain's people, perhaps? Dain himself seems unlikely, unless he were tricked or they were going for a massive redemption arc. I haven't seen anything to indicate that his role is big enough for the latter, though. But maybe he's got a shifty second-in command?
Or possibly I'm overthinking this.