New video with more information on the "Spirit: Riding Free" series.

https://www.youtube.com/watch?v=fXwS242oVfI

Apparently, the buckskin character featured is not in fact Spirit himself, but a mustang of the same name (this was done for copyright reasons).

There are many more models, characters from the series. Interestingly, (alongside the fact that the three main horse characters are a buckskin, paint and palomino - like Spirit, Rain and Esperanza) some of these other characters seem to resemble (in basic design) characters from the book series 'Spirit of the West'. For example, a black horse (like Strider), donkey (like Paco), a grullo (like Cedar), a grey (Bonita) and a chestnut sabino paint (Sierra).

A list of the new (named) characters has been added to the 'Riding Free' page:  https://www.animationsource.org/spirit/en/custom/&id_film=16&nump=9141