Since Nadu can keep putting lands onto the battlefield, you can keep triggering all your landfall effects to make an army of tokens
Regular Creatures, Sorceries, Enchantments, and more can only be played during their owners turn, but Instants can be cast whenever their owner chooses
Mana Crystals are the premium in-game currency
I'm not sure we've quite gotten to the bottom yet on Bloomburrow singles, but in most cases, it'll be better to buy singles you need now as compared to when cards first came out
Unlike Jeskai, they actually shut down in the face of Blood Moon, so you may as well try
While the green one is far and away the most versatile and easy to find a use for, none of them are unplayable, and all can slot into your mana bases without much trouble, especially given they enter untapped