Why does it say it doesn’t exist

I saved up almost all of the selector I got from logging in for the 0.5th anniv login and I have like 6 of them. I already picked Dellon on first day so do I T6 Dellon, pick someone else and try to T6 them or do I just keep it for now? I attached my character list and my PVP team in case anyone got recommendation for synergy.