I think that your modifications are headed in the right direction. I do have a few questions:
- How many levels are you planning on making?
- How are you planning on making each level unique and significant? Obstacles, challenges, and abilities can help you a lot with this.
- Be careful with how your proposed modifications intermingle - they all seem to revolve around level creation, so be sure that each can stand on its own.
I'm looking forward to seeing what you make!