I was thinking
Dora or Dora-related names would work for
Dolly, too.
Dorothea,
Theodora,
Eudora,
Isidora, just
Dora...
Or what about
Delilah? The sound difference between then is so slight, it could work. Or
Delphine (especially since that one is also related to dolphin. Dolphin,
Dolly? Yeah)