The rules state that a battery holder can be included in the charging system, rule questions say you cannot have a SEPARATE switch, but what if the switch is built into the battery holder? It's part of an accepted part and is not additional.

No. The rule lists the acceptable parts. Using a pre-manufactured charger with a switch is not just a battery holder. The rules do not include a switch in the charger circuit. Prior FAQ's have addressed this. Nothing in prior interpretations addressed "Separate" vs included switches. Only that there cannot be a switch in the charging system.