Indeed, a dead animation would be best, though the transfer to standing wouldnt be smooth, so if you want it to jump out from something, make sure that you trigger that object to explode/move and then the monster_maker, this would probably work best depending on your situation.
here is another situation with the use of sprites:
1 model: dead zombie animation
1 monstermaker: creating alive AI zombie
1 multimanager: triggering sprites
first, create a room/situation, il use a zombie near a steam pipe.
Put your zombie model there in its dead animation.
Put a few sprites near it with the same name and the flags:
start off
play once
make a env_render trigger the zombie model, make sure you put render fx to texture and fx amount to 0.
As soon as the player passes the trigger the mm gets activated. This mm triggers the env_render and the smoke sprites at the same time, making the zombie model disappear, a 0.5 second later you should trigger the monster maker and spawn your zombie.
Depending on the sprites you should chose the spawn times, i took this as a example.