oh yeah, its fine. The difference between the two formats is the banlists/ card blocks you are allowed to have cards from, thus leading to different deck types flourishing in one format but cant exist in another.
As per the creature...not entirely.
Gaea's Cradle doesn't have a mana cost and is land, leaving it open to land tutors,
Crop Rotation, and can be abused by untap triggers that alot of elf dorks have on them. I would recommend making some proxy's and playing with it to truly understand how it fits into a green elf deck.