Would this be at all possible using ACF for the fields? Yes.
How difficult would this be? Very.
Because of the relationship between users and “Posts” (i.e. “music”) you would have to add some type of a lookup table that relates each user to each post and stores the options the user has selected for that post. Then you would need to pass these values and update the lookup table in some way when the user provides input.
There are several ways to create the lookup table, but most application developers would create a new database table.
