Map Maker is most likely crashing from a made map, I've experienced the same problem with one of my maps. Go to your Feralheart > Media > Terrains folder and move the map folders and .map files (except for Watermill) outside the Feralheart folder, like your desktop. That might stop the crashing, if not you may have to re-install your game.
As for the paws and mane, well the mane is the same as felines. In your Feralheart > Media > Textures folder, there is a file called fmaneShade.jpg, that is the mane texture used for both feline and canine.
Shading for the paws are included with the body shading, if that is your question. When saving the mane it's actually .png and not .jpg.
Good luck! Let me know if you're still having any troubles.