Pretty busy at the moment but will try and help. First things first, you need to chunk up your questions to smaller and more specific one and I am sure someone will be able to help. You can also post in the Discord in specific channels about issues you have.
- There is no testnet/lightnode you can run. There is one instance of the replica that you can run locally for developing and testing. You can learn more about it in the setting up your dev env section.
- If I understand corectly you want to redirect a web2 Google Site page to a .ic domain ? If you move your frontend to the canisters deployed on IC you can link to domain names, no more need for google sites. There are examples of how to do that for main domain registrars.
I recomend that you and the team go and take a look at Welcome to the ICP developer journey | Internet Computer and ask questions along the way.