1. Duplicate this template to your Notion workspace.
2. Create your site using Super site, using your newly created page as the Notion URL. See this tutorial on how to create your first Super site.
3. Add Linkotion styling code (CSS) from your purchase to your Super site setting. Don't forget to use <style> tag.

Yes you can. Here's our Linkotion's documentation regarding customization.

Yes you can. Here's a tutorial made by Super on how to integrate Fathom analytic.