We read this as no switches on the power source. The input jack on the plane acts as a switch toggling between the capacitor, motor and charger. Many aftermarket charging jacks do not have a switch, 3 wire function. Can the plane have a "normal" S...

Yes, the plane can have such a switch. Switches are specifically permitted by para 3.f on the plane "The power system on the airplane MAY ONLY include a propeller, motor, capacitor, SWITCH, wires and connectors." Type of switch is not specified, so any is acceptable. Switches are NOT permitted on the charging system as they are not part of the allowed components. Again, para 3.f "The charging system MAY ONLY include the battery cells, a battery holder, wiring, connectors and a resistor." (Note capitalization is for emphasis, rules do not have those words capitalized.)