Best yet, the arrival of MTG Arena as an honest-to-God alternative to physical Magic: The Gathering is a lifesaver
The deck is a White, Blue, and Green (or, Bant) deck that revolves around creatures that enter with +1/+1 counters, that synergise with Tidus, Yuna's Guardian's abilities
Commanders like Runo Stromkirk and Serpent of Yawning Depths want you to play big sea monsters and even synergize with them, while cards like Whelming Wave reward you for playing them
Armorcraft Judge is another amazing support card for the archetype
Possibly--it would depend on the pacing of reprints compared against the rise in demand for them
Rakdos sacrifice has commanders like this already, but this one is actually good enough to compete and be played based on personal preference, which is a first with this set