What expansion packs are used and will you ever make a download? This is so awesome, it's the best set of the Mane Six I've seen in a while and I wish I could use it too or know what expansions would be needed.
As I stated in a previous comment, Spike technically should be a kid, but I have him as a teenager for gameplay purposes. Teens don't need to be cared for as much as children Sims and teens have more customization options. I do have a child version of Spike and he probably should be a kid in game, I just personally prefer to have him as a teen for my Sims 3 game.
In Sims 3 you can choose up to 4 colors in each Sim's hair (roots, base, highlights, and tips.) I could not recreate Rainbow Dash's hair with all 6 of her colors, so I chose what I thought would match best by using all cool colors (blue, green, and purple.) It may be difficult to see in this picture but the roots of her hair are purple and the tips are green.
I actually have made a child version of Spike, but I don't use him. I prefer his Sim to be a teen instead of child because teens can care for themselves and I wanted Spike to be able to take care of himself. I didn't want the Mane Six watching over him all the time. Toddlers also have fewer interactions and less customization options. Though teen Spike can be rebellious at times and he loves to scare Fluttershy, despite him having good and friendly as traits.