#1 - June 8, 2016, 7:56 a.m.
The model supports particle colour customization, so this could very easily be done for this mount. It only requires a new entry in ParticleColor.db2, and tweaking of the entry in CreatureDisplayInfo.db2 to reference it.
It could very easily just use the same particle colours as the original green core hound from Shadowmoon (Outland), the values of which are (red, green, blue):
start: (58 , 208 , 24), middle: (100 , 255 , 24), end: (191 , 255 , 19)
Or in #RRGGBB hex notation:
start: #3AD018, middle: #64FF18, end: #BFFF13
I can show you the difference in WoW Model Viewer. While WMV doesn't render all the effects right now it can show you the difference in fire.
This is the mount with the current (default) fire colour: http://forums.wow-petopia.com/download/file.php?id=26618
And this is with the particle colours altered to be the same as the old green core hound, using the values I gave above: http://forums.wow-petopia.com/download/file.php?id=26619
Thanks for your consideration :)