Ah, thank you for the suggestion! A lot of people have said Spectrum, I believe I'll probably use that.
The only names I could come up with so far are; Rainbow Prism, Neon Spectrum, Rainbow Scribble, Doodle Heart, and Neon Spark.
He's kind of a jack of all trades, and I haven't really come up with a cutie mark for him yet, which adds to the difficulty of names.
I'll definitely keep it in mind, and thanks for the PM offer! I appreciate it