10 Nov 2023
Admiral Brass, Unsinkable's effect will overwrite any previous effects that set the returned creature's power and toughness to specific numbers. Effects that otherwise modify the returned creature's power and toughness will still apply no matter when they took effect. The same is true for +1/+1 counters.
10 Nov 2023
Multiple finality counters on a single permanent are redundant.
10 Nov 2023
Finality counters aren't keyword counters, and a finality counter doesn't give any abilities to the permanent it's on. If that permanent loses its abilities and then would go to a graveyard, it will still be exiled instead.
10 Nov 2023
Finality counters work on any permanent, not only creatures. If a permanent with a finality counter on it would be put into a graveyard from the battlefield, exile it instead.
10 Nov 2023
Finality counters don't stop permanents from going to zones other than the graveyard from the battlefield. For example, if a permanent with a finality counter on it would be put into its owner's hand from the battlefield, it does so normally.