BEST FRIENDS BABIES
I always thought Hasbro's logic for naming these ponies was a little odd - although it wasn't the first time MLP had used humanish names, it was the first set which seemed to make a theme of it.
For the record, Baby Billie is a GIRL - BillIE is a traditional female spelling of the name as a short for names such as Wilhelmina, and she is mentioned as "she" on the backcard.
Though loosely in the line of some of the previous ponies-and-pets releases, this was definitely the budget model. The set comprised three baby ponies, with monocolour body and hair, and all of which in Earth pony styles. Their symbols were also monocolour, matching the shade of their hair (at least loosely).
Each baby was sold with a tiny rubber 'pet' which also matched her colour scheme. These are extremely easy to lose, so much harder to find on the second hand market.
The pet was also sold as a free gift on one of the later issues of the My Little Pony comic (which was presumably a way of getting rid of excess stock).
Although they were not necessarily available until the end of the MLP line, they were one of the sets which seemed to have been made in vast quantity, because MIP ones in German packaging showed up for some years at discount prices in the UK after My Little Pony ended. (To put it into perspective, I got all three of them Mint in Package in 1994-5 for £2 the three)
There is also an amount of mystery associated with this set. On the original 1993 pamphlet, two of the babies from the set - Billie and Katie - were wholly misrepresented. Billie was shown in pastel colours and Katie in the looking up baby pony pose, when she was actually sold in the shy pose.
VARIATIONS ON A THEME:
Best Friends Baby Ponies (the ongoing mystery)
Pose variations of these ponies also exist. To date a Susie and a Billie have been confirmed, but their actual source of origin remains a mystery and as far as I know, only the one Susie and only two Billies have ever been unearthed. There has never been pictorial evidence of a Baby Katie. All babies have the same hoof stamps and place of manufacture as their original version. Check Baby Susie and Baby Billie's pages for photos of the 'alternates'.
There are a number of theories about what the reason for these variations are, though noone knows 100% for sure which, if any, are right. Some of the ideas are as follows:
1: These were a form of prototype (although if so, they are not the prototypes used in the photo advertising, so this seems unlikely)
2: These were mistakes where the manufacturers got the poses and ponies switched and were supposed to be withdrawn, only some slipped through the net (this is not verifiable).
3: These were genuine variations sold in a different place (although if that was true, surely more should have been found by now?)
4: They were part of a design test production, after which Hasbro chose which ones they wanted to manufacture, and discarded the rest (though they are perfectly made, so there is no sign of experimentation at work)
Whatever the truth, the variant poses are probably some of the rarest My Little Ponies in existence.
(In contrast, the ordinary versions are fairly common on the Second Hand Market!)