Sorry for the late reply, but I'm failing to see how this is even a concern? The only Baby pony that was given multiple version is Baby Lickity Split, as she's in both the Beddy-Bye Eyes and First Tooth sets, and then the only accessories she has in common between releases are the aqua duck comb and white ribbon.
Play and Care sets and BBE sets both had playpens, yes, but of the 5 babies that came with them, the colors are all different for each pony (see
http://mylittlewiki.org/wiki/Playpens_and_Blankets ). Otherwise, Play and Care came with rockers of various colors, while BBE came with high chairs and wagons. So, unless you're referring to combs and ribbons, there is no repeat for accessories.
Unless I'm seriously misunderstanding the question?