I’m hoping someone can explain why each of these is good or bad.
︎ [U+203C, U+FE0E] - double exclamation mark emoji(Unfortunately, Discourse corrupts my post, so I can’t actually write U+203C on this platform.)
(In the cases where I’ve run into these, I am 99% sure that the artist did not intend to interrupt their title with a (differently-colored) emoji.)
No reasons to use an emoji version (U+FE0F).
And I don’t like to use any invisible characters anyway, not text variation selector either (U+FE0E).
Then single double exclamation mark character or 2 regular exclamation mark characters… I would leave it up to case by case… 
U+203C is good IMO, I have used it in some MB stuff like 愛をとりもどせ‼ because on the covers it looks like a single character (diagonal twin exclamation mark).
Ah there it displays nicely, when in sentence.
I think that is also my answer. I would always go with option three unless I knew for sure the artist was addicted to emojis. For now many other platforms will be like discourse and fail to print the character due to font limitations.
Option 2 is not an emoji, it’s a regular character, but Discourse formats many characters (curly quotes, removes nnbsp, nbsp, etc.),
They have a text cleaner.
Don’t decide from what Discourse accepts or not.
By the way it did accept the character in my post, when part of the work title (see option 2).