Your post is a little hard to follow. I think what you are saying is that to be trained as SIC the trainer must be a CFI. That is incorrect. Any Type Rated PIC can train an SIC in the aircraft as the trainer per 61.55. Very basic training to be completed in the aircraft or sim (I did it in the aircraft). Once the training is complete the SIC can act as SIC even with a single pilot type rated PIC as long as they stay SIC current.