From the ASN referenced TV news report by an eye witness to the accident, it appears that the accident aircraft was part of a flight of 3 such aircraft, performing a formation flight, as is typical for airshow flybys.
If the accident aircraft was a wingman, it is probable that only the flight lead would have been squawking, and thus there may not be ADSB information from the accident aircraft.
I do not know what the AT-6 flight manual might say on the subject, but the roughly comparable T-28B flight manual directs gear up landings for any off runway events.