Questions about acceptable 'Fluff' infomation.

[Amaterasu]

(Mark would still have the final say in this)

I believe that both versions are acceptable and wouldn't require you to seek approval for them, because they are "explanations" of how your power works, and don't strengthen or otherwise improve your move. Saying that your character fuses to someone by sticking them in their armor sounds just fine to me, same for the Sonar - just keep in mind that you cannot use the Sonar thing as an excuse to circumvent Suppression that would block it etc. but I imagine that you were aware of that.

For reference, there's been people using Fusion ranging from giving someone else an item to turning into a weapon for the other to use, and Enhanced Senses have been used as an explanation for smell, Sharingan eyes etc.