Practically straight, Ella is combined with Pollux. But other than that it's pretty correct.

When they were shouting that, they were actually talking to the spirits and using their shamanism, they are so compatible because they all share the gemini attribute, which is responsible for the teleporting aspect. 

Ruber and Venetus as servants, can't do any shaman magic, they can only use their NP's. Hence Ella had to fuse Castor into the sword for Venetus to use.