Hi Wreckbot,
Welcome to C2.
As both the tutorials you've mentioned are for learning purposes, I'm fairly sure it would be okay for you to use what you've learnt from them, to create your own project (especially if you are using your own media).
With regard to your other question, it would be worth checking out the 'How do I' section. Where you can find information on:
1. "Multiplayer/Networking"
2. "Making a title/menu screen"
3. "Variables (Local/Global/Instances)" - you can use these to store information regarding locked/unlocked levels
4. "Webstorage" - you can use this to save game data between sessions.
Good luck, I hope that helps to get you started :)