Yes, of course there are 'favorites' in the system. For instance one alter fulfilled some attachment needs. She is likeable and charming. Another is 'spunky' - she is witty and funny and likeable in a rogueish kind of way.
Others dealt with not so nice stuff, so of course they are not 'favorites' with anyone. Some were favorites with abusers, and definitely not with us.
Some were/are favorites because that was their job to be that way.