If they did the vehicles and armor transformations, what I could see being done.
Desco: Grappler Ship; an homage to "Outlaw Star", a purple ship in her design, her claw things become the grappler arms, and there is a fluid filled control pod at the back with Desco's humanoid body in it.
Prinny: Rocket Ship (would kind of resemble more a kiddie ride)
Alraune: Hopper (kind of simplistic, but its more for the
factor), your humanoid character would be standing in the flower as it hops while the Alraune's body is bent over in front of them, their hands straight out forming a "Flower cannon" (like Lillymon from Digimon).
Sludge: Body Armor, body coated in slime and wearing its skull.
Orc: Motorcycle; old school and you get the helmet.
Spirit: Body Armor, you wear its coat and have white body armor.
Shroom: Mech-suit, very Motango like, or kind of like a comical version of Zeram.
Dragon: Tank, dragon head for the cannon, two little wings, scaley tank body.
Sabrekitty: Armor, you are wearing the fur and claws like a tribal warrior.
Zombie: A bi-plane, bone propellor, green rotting body, zombie head for the gun.
Mothman: Jet, claws on wings, color, so kind of a yet.
Cu Sith: Zoid like rider, it barely changes, except now it is mechanical and you ride on it.
Succubus: A drill car or a Motorcycle, I am partial more to the drill car, would have a batmobile feel to it.
Gargoyle: Helicopter (large civilian design)
Roc: Hopper, its tail is the spring and your humanoid is riding inside its mouth using the antlers as a steering bar.
Nekomata: furry motorcycle.
Shinigami: Black Helicopter with sychte blades. (military Apache Helicopter design)
Baciel: Tank, cannon arm is the cannon of course.
wood golem: armored vehicle, kind of like the one in the new Bat-man movies.
Skeletal Dragon: Mech-suit, its wings are now jet wings, skeletal armor, the horns, kind of evil Gundam like.
Priere: Going with a sleek black and red Akira style motorcycle.
Gig: Armor, like serious evil Gundam god armor.