I doubt he went to the Hutt's, just that the messages were sent in Huttese. Well some of them, and hopefully the ones we want. Huttese was and still is a pretty common, if inelegant language in the galaxy. Can Denz take a crack at all this?
The corrupted data, and checking for messages sent in Huttese, perhaps the latest entries if that can be discerned.
I think Ush just established that it probably WAS the Hutts that Darth Kazan used. They would be a neutral party in any war the Jedi and Sith fought, after all. They still are in the Prequel and Original Trilogies. Denz would probably be best at taking a crack at the encryption with his high Fix-It skills!
Gallagher does not have much to contribute in the way of skills, if Jedi Lore does not qualify. Maybe he can help Jelena with tracking down Huttese messages and translating them. He's not bad with Language.
Could Savoir-Faire be helpful here in some way? Knowledge of the Galaxy?