I think that the bridgeman kaladin slaved might be relevant later, but I don't think he's Taln or a Herald. Now, I can't disprove the last one (anyone could be a Herald) but this is why he can't be Taln:
Sacklike clothing: Bridgeman wear a vest and trousers, not a sack.
Description:
Here is how the bridgeman is described: "He had dark brown skin and brown eyes, his thick black hair pulled back into a long, braided tail."
And here is Taln: "...a solitary man with dark skin. His hair was long and matted, his clothing nothing more than a ragged, sacklike length of cloth wrapping his waist. He stood with head bowed, wet, ratty hair hanging down over his face and mixing with a beard that had bits of wood and leaves stuck in it." He's also wild, dazed, and wet. It doesn't sound like that's someone who was just healed on the battlefield, but one who came from the fires and the pain that was described in the prelude
Also, Hoid seems to be there specifically to greet Taln as he came back. Why wouldn't he just find him in the Shattered Plains?
I admit, the accent thing is weird and the description is similar, but I don't think they're actually the same person.