you can have a doll party with your other dolls. it does not have to be a monster high doll party you can use all your dolls: barbie dolls monster high dolls moxie girls moxie teens that kind of stuff and you can mix and match the doll's] cloths!!!
It depends on what operetta doll you are looking for. You can usually find any kind of operetta doll in any kind of toy store. Look everywhere you can and you might be able to find the operetta doll for monster high that you are looking for. Thanks!