Yes, I think we will hear him talk this episode. If Korra is going to be trapped in that confined space for most of the episode then we’re not going to get just flashes on Aang.
Hopefully we’ll get fully fledged flashbacks and perhaps even Korra will contact him fully in the Spirit World. Mike and Bryan did say we would see the Spirit World in the Legend of Korra and it’s completely plausible it’s in this episode.