The audio exists for all the missing episodes; if anything is missing then we're talking about brief cliffhanger reprises which are duplicated on the episodes surrounding it.
Certainly The Ice Warriors has a complete soundtrack - the 17 minute long recon was one specially made for the VHS release when it was determined that a full-length reconstruction would be impractical for general release, however the complete soundtrack was included as a bonus CD with the release. Numerous complete recons of the missing Ice Warriors episodes have been made over the years.
And there are 6 complete Troughtons (The Tomb of the Cybermen, The Dominators, The Mind Robber, The Krotons, The Seeds of Death and The War Games) as well as 2 almost complete (The Ice Warriors and The Invasion, both of which are missing 2 episodes out of 6 and 8 respectively). All the other stories have at most 50% existing and aside from the recently-discovered second episode of The Underwater Menace have all been released on Lost in Time.