Okay, after looking through the limited Palutena footage again and taking a frame by frame analysis, I definitely missed something.
When Palutena activates Lightweight, she doesn't have her halo. Every special, and every smash shows her activating her halo when using a special attack. This leads me to believe then, that Lightweight may not actually be a side-special ability, but a buff similar to the Wii Fit Trainer's Deep Breathing special - activated by down-B. So with that understanding, Lightweight is probably a similar case; a buff on down-B, rather than a side-B special attack.
This basically means that Celestial Fireworks can't be a down-special. Both Counter and Reflect are defensive moves which traditionally find themselves on down-specials. Fox, Falco, Marth, Ike, Pit and others all had a defensive move on their down-special. The one exception (that I can remember) is Mario with his cape being a side special. However, I think that Mario is the only historic exception given he was the first character to really have a defensive option.
So where does that put Celestial Fireworks on the special list? Traditionally, projectiles are usually neutral specials with very rare exceptions (secondary projectiles, like Samus' Missiles, or Link's Boomerang) being a side-special. This means that at least one of Palutena's projectiles has to be a side-special, but I don't think its Celestial Fireworks. I think that Celestial Fireworks is a neutral special and that Auto-Recticle may actually be the side special. Partially because I think its main function is similar to Zelda's Din's Fire, another side-special. Auto-Recticle likely operates the same way as Din's Fire; meaning that its guided by the player and eventually detonated by the player or after a set time, just as I said in my last post.
So with that said, I still think my default move list is correct, but I now think that Auto-Recticle is a side-special and lightweight is a down-special buff type move.