Baby Cotton Candy and Baby Lemondrop were definitely available in or around 1987 according to Hasbro.de's promotional material. The scan above comes from the 1987 promo booklet I have.
Baby CC is probably also an earlier release from the set with painted symbol baby Glory and Baby Moondancer, so it would be interesting to look at them and do comparisons on the hooves.
But as far as I know from the information I have, Baby Lemon Drop in the blossom pose (baby Zitroenchen I think?) is part of the 1987 set with Baby CJ (Kirschblute?) and so on. And Baby CC (Karamell) is also part of that set.
Which Baby CC you had depends a lot on which card she came on, but I have no idea how this influences the hooves. European and UK ponies are my speciality but I haven't spent a lot of time on the Pat Pend aspect as it's more of a niche variation issue than a wider release issue. I think PKW, you definitely know more about that than I do. xD.
I have Baby Kirschblute's card (I think it's hers, it may be Hopsi's...) in my collection, and it is actually more of a 1988 card design than a typical 1987 card design. It has the narrow border around the edge that you see on the European TE release, the German/French Princess release, the european/uk Party/TAF pony release, etc.
There's some room for flexibility on dates of release and the styles of cards but it does give some indication as to what was going on when. At the very least, 1987-8.