dimensions? biomes?

I need help with dimensions and biomes.

Biomes

     I want to make biomes have different heights.

         (example: my mountain biome will have mountains, my plains biome will be a bit flat.)

Dimensions

    1 - I want a dimension with a custom deepslate and custom bedrock.

    2 - I want to make items be the portal igniter, like nether portals use flint and steel.