The "whip stalls" prohibited in the Aerobat are tailslides.
Per its certification basis, all aerobatics are approved except for those prohibited. Stall turns or hammerhead turns are not listed in the AFM with a recommended entry speed but are not prohibited therefore permitted.
Nil oil pressure inverted as well so the limitation on inverted flying.
Ex-Cessna test pilot Bill Kershner has an excellent book on aerobatting the Cessnas.