For gamma, I brought in a yuty, rhino, and 18 (unleveled) direwolves, yes, direwolves, the dragon ignores the direwolves the same way it does for megalosaurus and deinonychus. I brought the rhino as a backup plan and it didn't help, the dragon just focused it and it eventually died. I eventually won

For beta I brought in a bunch of incredibly leveled creatures including three stegos with 60000 health, a daeodon with 75000 health, a yuty with 100000 health, and a mammoth with 80000 health as well as all the remaining direwolves (13 total). I rode a stegos while blasting the boss with anpowerfull shotgun, The two other stegos died as well as 11 direwolves. I eventually won (P.S. I had all the direwolves named after fictional characters and the only two to survive we Peter and Lois Griffin)

For alpha, I haven't done yet, but my plan is to use a rhino that deals at least 28000 damage per fully charged hit, as well as a possible mate for the rhino (for increased damage) Another leveled yuty, another leveled daeodon, probably 10 high damage direwolves, and 6, 25000 health stegos (rest of levels into melee)

Another idea is to bring a rhino, a yuty, and 18 stegos all on separate tame ordering groups, each time the dragon lands, you send one or two stegos and tack a ton of damage on by using the rhino while the dragon is distracted, once those stegos are dead, you send the next and repeat until the dragon is dead.

These alpha ideas are quite possibly terrible so, don't lay all your trust in them