I am not so sure what exactly you're up to. If you use ent_clone and ent_morph later on you're just wasting memory, because the cloned data remains in memory. ent_clone is pointless anyways when you use ent_morph later on. If you really need this I'd just go the simple way:

1. Create the entity.
2. Use ent_clone as you see fits.
3. Instead of using ent_morph remove the entitiy. (This will free the cloned data)
4. Create another entity with the file you would have selected in ent_morph that replaces the cloned one.