Do all these additional lubricants help to maintain the car parts ???

Snake oil, and they can do more harm than good. The fluids in your vehicle involve some complex chemical engineering, especially engine oil and transmission fluid. They contain specific additive packages that provide certain properties for the application in which they are used. These involve a careful balance, as certain additives will affect the properties of others. When you add some magic potion, you are essentially tampering with a specifically engineered product. Hopefully it wil do no more harm than lightening your wallet, but in fact they may affect the performance of what is already in your vehicle. Think about it; your car is a complex piece of equipment that a manufacturer has spent millions or perhaps billions in development and design. If any of those miracles provided any measurable benefit, wouldn't the automaker already include them?