The best idea for that is probably just grinding color areas because of the identical color exp boost. You could evolve those cloudgolem evo materials (or whatever they're called) but that seems like more trouble than it's worth. Some sidenodes do have witches tho, if you manage to get them and want to use them on that.
Also, just to put it out there, I put my ingame name as Darknezz.
Nah, just wait for Zuma/WTC Guerilla dungeons for ez exp.
EDIT:
Upcoming events:
8/13~8/14Solar Destroyer Demon King Pyrante descend100% rate to obtain Pyrante, evolves to Stygian Overlord Pyrante
PS: Deals high Fire damage every turn (x7? x10?)
Active: Increase ally attack by 200% for 1 turn
8/14~8/21Ensemble Schoolgrounds - Chance to obtain Luiza, evolves to Fashionista Luiza (D; PS: -10% D damage, Active: 1 Turn Delay)
Jade Circus - Chance to obtain Pia, evolves to Verdant Enchantress Pia (G; PS: -15% G damage, Active: 5x Healing)
8/15~8/18Starlight Ridge - Chances to obtain Red/Green/Blue Pikas.
Hope of Perennial Revolution - Chance to obtain Azure Dahlinia. Azure Dahlinia requires 5x Red Pikas to evolve to Floral Fairy Dahlinia.
Wish of Perennial Sorrow - Chance to obtain Floret Lyndau. Floret Lyndau requires 5x Blue Pikas to evolve to Floral Fairy Lyndau.
Field of Full Blossom - Chance to obtain White Lily Yurika. White Lily Yurika requires 5x Green Pikas to evolve to Floral Fairy Yurika.