Fizzling Shattering Crescendo

I have some questions in regards of Shattering Crescendo and possible fizzle scenarios:

A vampire plays Shattering Crescendo at superior melpominee targeting two War Ghouls. The controller of those War Ghouls sacrifices them to burn two different locations.

1. Does the action fizzle? Card says "up to two targets", but targets are chosen when action is declared and they are no longer valid, so I guess it fizzles.

2. In case it fizzels, does the acting vampire controller need to discard a Shattering Crescendo from their hand?

3. In a different scenario, where targets are still valid on resolution, but vampire has lost blood during the action so they cannot pay the blood cost of the action, does another Shattering Crescendo need to be discrded? (similar to question above but different reason)

Thank you

Shattering Crescendo - Action
Protean: Ⓓ Inflict 1 unpreventable damage on an ally or retainer.
Melpominee: Ⓓ Discard a Shattering Crescendo to inflict 2 unpreventable damage on each of up to two minions controlled by a single Methuselah.
Superior Melpominee: As Melpominee above, but for 3 unpreventable damage each.

I foudn the aanswer in a different thread
www.vekn.net/forum/rules-questions/81642-shattering-crescendo-and-missing-target#112150
the action fizzles if there are no targets left.

Hobbesgoblin wrote:

I foudn the aanswer in a different thread
www.vekn.net/forum/rules-questions/81642-shattering-crescendo-and-missing-target#112150
the action fizzles if there are no targets left.

Thank you! So now we are sure that the action fizzels if it does not have any valid target.
But I still have the doubt about discarding the Shattering Crescendo. As far as I know, when an action fizzles, you pay cost as much as you can, but is this also affecting to this discard cost/effect?

So in general, if I'm unable to pay the card cost in full (e.g. because a modifier cost), effect cost has to be paid?

(in that Discord thread we were not 100% certain which was the case iirc)