Yes, both have to be on XX
Weve specified that once a player chooses to stop spending actions and ends their turn, they forfeit any remaining actions they may have until step 4.2 of upkeep
Nahiri, Forged in Fury is much more suited to Bracket 3
The benefits to many of these cards are apparent, but here is a complete list of potential that we scribbled down, in case you dont see it: Scolding and Lance for protection purposes, Eater for recurring Tribute fodder, Hats to get Penalty Box into Graveyard, Battle Fader to block OTKs while setting up a Tribute Summon, Gusto so that you can use Creature Swap to setup Jersey OTKs while maintaining a floating wall of Tribute fodder, BA for access to floating Dantes and triggering something off of Perfect Ace, Maxx C to let you passively wait out your opponents plays, and Cardcar to offer another source of draw power if needed
The land will always be Gold Foil but has a 75% chance to be a regular Full-Art land and a 25% chance to be a Full-Art Panorama land
However, with too many upkeep payoffs, you dont get as much value