Wouldn't it be cool if Nightheart was actually named Nightmist?
Not only is it fucking rad, but it still incorporates his inspiration from Nightcloud and actually succeeds in what he wants. An original name. But it also has a weird call back. Nightmist is Sparkpelt's kid. Sparkpelt is Bramblestar's kid. Bramblestar is Tigerstar's kid. Tigerstar's dead siblings were named Nightkit and Mistkit.
Lol random, amirite?