Survivors and killers, licensed and unlicensed, can be bought using auric cells. Just not with iridescent shards if they are licensed.
when jeff and legion left, they bought them but they were not replaced by other characters, but this time they were jane and the plague was exchanged for the halloween dlc that happened
It could be possible, but we don't know for certain. It could also have been an oversight.
However, it may be likely that Halloween may be seeing some new cosmetics, since the movie last year was a success, and the Halloween license is the devs favorite DLC, so we'll just have to see. Ash is getting some additional buyable cosmetics when he releases in two days, so we might see others get some too.