2d spritesheet animations runtime loading (from tps file to dynamically spawned animation)

Hi to all,
I'm relatively new to Unity coming from a background of cocos2d-x so my doubts.

I'm searching for reference to do the following.

1) Compress 2d object animations in a texturepacker file (or any other atlas format if possible)

2)Load it at runtime from resources folder

3) Spawn animation loaded from atlas on scene

We're building dynamic scenes from xml files to spawn background,animated elements and other thing.

I've seen the texture packer importer and other plugins but I couldn't find a way to do this without interacting with the editor.
We need a way to spawn dynamically the scene with the game objects decoupled from the editor to allow artists and game designers to customize and test their assets without rebuilding the game or using the Unity IDE.

Thanks in advance

Francesco