I just got Pepper Parson of the Pinkie Cooper range and of course I had to check, if any of the existing shoes would fit her. Unfortunately, it looks like only boots will fit, because the doll's feet don't need to go all the way into them.
Here is the doll wearing Barbie boots from 1970's.
A closeup from the side shows that the boots aren't a perfect match, but they look like this on most other dolls as well.
Another pair of boots that fit are these white cowboy boots I have originally bought for Blythe.
However, the best fit comes from a Re-Ment set. These look very nice and just the right size.
No other Barbie shoes than the brown boots fit the doll, but these Barbie leg warmers look quite nice on her. I might try making something of ballet shoe type to go with these.