It will last until the game ends or the affected creature leaves the battlefield
Since the goal is triggering landfall not necessarily having a lot of lands dont be afraid to include ramp spells that require you to sacrifice lands, like Harrow and Crop Rotation
Giving either legend protection from blue and black is a fantastic mode, and while youd like to be immune from Path or Swords, this covers most of your other bases
In each 12-card booster, you'll find: 1 Mystical Archive card (uncommon, rare, or mythic rare) 1 Lesson card of any rarity 1 Traditional foil card of any rarity* 1 Card from The List in 1 out of 4 boosters (*This includes global Mystical Archive cards in all non-Japanese Set Boosters, and both global and Japanese alternate-art Mystical Archive cards in Japanese Set Boosters.) Plus, you get a delightful art card, 1 in 20 of which feature a foil-stamped logo or artist signature
A little bit of quick maths, and 9 x 14 will result in a pool of 126 cards to choose from
Even though Naturalize isn't breaking colour pie it shows the willingness to do adventurous things and I am all for it