It looks like around 4 each of the non-gear or weapon parts (head, ears, arms, etc.) are available currently in chests without the expansion packs. I just found half robot ears in one.
There's a new music effect (8 Bit) in the Ro-Bow pack and a new voice effect (Spooky) in the Wildstorm pack. I was hoping for a new voice or 2.
All of the new weapons and set parts look like they're only in the level packs...not sure if that means you get them instantly when you add the packs, if they're only in chests found in the new levels, or if they're available to be found in any imaginite chest once you've added the new levels.
Well, they are probably from the radios in each of the new levels they had to have something for those since there is one in every level.
I have a feeling that the new parts (at least most of them) will only be available from chests in the new levels. They already have a way to limit what kind of part you will find in a chest - like on the first level in the cave you always get a weapon even if you have them all, they have Spyro scripted to tell you how cool the new weapon looks. I doubt we will be able to grind out the first level and/or the Undead zone to get all the new parts, but maybe once you unlock the level they can appear in any chest.