how to make entity dance through procedure

If u want them to dance if a certain song is playing I would instead set a NBT tag on the block on right click instead. Then on the blocks tick update in a radius of the block check for the mob. If the mob exists in the radius and has the tag make the entity the play the animation.( make sure u set a tag on the entry so the animation doesn’t repeat.)

also the entity wouldn’t be the event target since ur checking if player right clicks block. It would just be the block not entity.

you could use the block "for each entity at xyz with radius n, as entity iterator, do"
if: entity iterator is of type weiss = true,
then: play animation and change texture. 

unless you want to use the entity on tick update procedure, to check for noteblocks with the correct disk within a certain radius. 

1: Ur gonna need to mark the jukebox with a NBT(so u can check it across different procedures). Then on the entity tick update check in a radius if the block with the NBT exists. If not have a cancel animation to cancel the animation.

2. Use the if entity is hurt condition. If true then cancel the animation.

3. Just use the override motion block and set all to 0.

but wouldnt the animation just start again at the next entitytickupdate? maybe a custom potion effect that is applied upon damage, and prevents the animation from starting. 

event: entitytickupdate
if NOT entity has potioneffect,
then if block with nbt exists
play animation

if starting the music is supposed to pacify an angered mob, that you have hit prior, the entity iterator procedure can remove the potion effect, maybe with a certain probability.