Custom Substrate Mix

I’m getting my very first snake, (Yayyy) but I’m unsure what to do for the substrate. I want to do a bioactive set up eventually, but for now I was gonna mix together coco husk, and coco fibers. So, a few questions:

1. Should I add top soil too? I also have play sand I could mix in as well.

2. If I were to switch to bioactive soon, would that just stress out the snake?

3. Does the enclosure have to be bioactive and have live plants?