First, before having any rust protection done to the vehicle, make sure it doesn't voild the manufacturer's warranty. As far as the rust proofing, I'm not sure what #1 module rustproofing is. Can you describe it? As far as the other, anything that uses an oil base is good. Oil will always help stop rust, so that would be my choice. Infact, many people where I live will actually save their old oil and spray the underside of the vehicle, doors. With the old oil and drive on a dusty road to make it stick. It works really well.
As far as the powertrain warranty, if you properly maintain the vehicle, you shouldn't need the warranty. I would save the money and put it away in case you need it.
Please remember, I can't see into the future, so I can't guarantee anything. However, history has shown that these types of warranties are not needed. Also, usually they only cover items that don't go bad or go bad because of lack of maintenance. As a result, they don't cover the repair.
All I can offer you is this. With aprox 30 years experience I have found that proper maintenance always works best. The insurance companies know that and will fight you to prove you didn't maintain a part that has failed.
If you have other questions, let me know and thanks for using 2carpros. Com.