In step 2, there are no replacement effects to be applied
On the other hand, you risk losing strong, archetype-specific cards
Players can't respond to your choice of +1/+1 counter or haste, and they can't take actions while the creature is on the battlefield without one or the other
These include cards such as Avatar Aang (flying, firebending, transform), Aang, at the Crossroads (Ally fetch, transform), Boiling Rock Rioter (firebending, Ally reanimate), Earth King's Lieutenant (+1/+1 counters), Fire Lord Zuko (firebending, +1/+1 counters), General Tazri (Ally fetch, anthem effect), Hakoda (cast Allies out of your deck, protection), Katara, the Fearless (double triggers), Katara, Water Tribe (vigilance, 1/1 counters, waterbend), Sokka (menace, prowess, 1/1 tokens), and many more
Ken Nagle suggested something pretty radical
Afterward, we'll explore cards that can be added later if you want to continue playing the Uta leader in other tournaments