Need help deciding my core

Ok so right now I have: Wolf Warrior, Fire Mage, Forest Guardian, Ent, Medusa, Alchemist, Hoyden Goku

I'm new to the game (like 3 days) so I need a bit of help deciding which units to throw out and which 2 or 4 to work on. If I'm missing an essential type of unit please let me know Also which ones should I evolve first