Of course you could argue that it is a difficult game for humans to understand as well =) So it might not fit exactly what you prompted for.
If AI teammates were allowed to have a pre-developed, shared model between them for communication so the other automatically "knows" what the others moves mean then it would be closer to fair grounds but that's considered cheating even though human teammates do the same thing.
On the other hand, I worked at a US Team Trials championship game, and the two tables were in separate rooms, with a diagonal partition across the table and completely silent bidding. Presumably they wouldn't go through such gymnastics if cheating weren't a concern. Perhaps the stakes are too low at the regional level (or those who are good enough to get away with it quickly progress to a higher level?).
Sort of, except you have to tell your opponents what your algorithm is. Like you can invent a system where an opening bid of "one heart" means "I have exactly three aces" (as opposed to the conventional meaning of "I have a reasonably strong hand with hearts as my longest suit"), but you can't keep that meaning secret.