Will be ever see the 3 Pokémon that fuse into silvally?
No.
Do you think it took 3 pokemon to make Silvally?
>>33454818
Tail
back legs
front legs
>>33454893
>no body
>>33454893
Silvally's thing is being made of as many pokemon as possible to reach Arceus's level of power, but being a failed experiment. Not only that, but it also evokes a frankenstein's monster, with it's composite look, that's combined into a griffin-esque shape. Not to forget:
Type: Null - Bronze helmet (which looks somewhat like Arceus's ring around the collar portion).
Silvally - Silver mane.
Arceus - Gold ring.