IMO...
'Teddy Bear' yorkies look like teddy bears, they usu have longer snouts, erect or floppy ears, large round eyes, usu have longer legs & are usu bigger than smaller yorkies.
'Baby Doll' faces faces have big round eyes, short snout, small face, & small ears & usu small cobby body w/short legs.
They're just words to describe a certain look on a yorkie puppy, but some unscrupulous breeders do use those terms to get extra cash.
1.This is Mimi's 1st born daughter, biggest in the litter & I would say she's got the teddy bear face.
2. This is Momo when he was a pup...he was advertised by the breeder as 'Baby Doll' face.