Even though I still haven't pulled a dang mixedup gravedigger, I can tell you that key strategy for them in your deck are cards with the "when played" ability, so you double up on or more with some of the abilities like pogo bouncer or flamenco zombie but one problem with that is if you get the flamenco first that is only two damage for all those dancers to set it up.
Thats the same reason why headstone carver is no use. More often than not he will come out last and be wasted.
Graveyard environment would be better if you want to still go that route, but keep in mind that everything resets when they go into the gravestone...bonuses are wiped away just as is damage