Does anyone know??
Your link isn't coming up.. did you buy purple candy melts?? You could melt it and add it to your ganache, and you could also just use puprle candy color (an oil based food coloring).
Any coloring should work for ganache. I would not use candy melts myself. They are used when convenience is the deciding factor, not taste. For something like ganache, use real chocolate.
If you added them into real white chocolate ganache it wouldn't be too bad. Just so she could use what she has. I don't care for candy melts either.. they are waxy and odd.. but mixed in with white chocolate it wouldn't be so bad.
Oh please use good white chocolate tinted with candy coloring (oil based) as mentioned above. Save the candy melts for making candy clay (so easy and fun to make). Candy melts have hydrogenated palm kernel oil instead of cocoa butter (hence cheaper and not made for taste).