Pony models can be pretty random. Basically you should prompt for everything. If you don't put the hair color in, you may get a random color depending on the check point you use.

I used a few different checkpoints with demo images. Same prompt.

Tania Raymonde Helen Katz (born March 22, 1988) is an American actress. Her roles have included Cynthia Sanders on the Fox sitcom Malcolm in the Middle between 2000 and 2002, followed by the Alex Rousseau in the ABC series Lost from 2006 to 2010. She has appeared on MTV's Death Valley (2011),