I generally encourage people to move towards bioactive enclosures if they can. I have all my geckos/frogs in bioactive setups, but have only recently started to move the snakes over. In regards to your first question, I think a hognose snake would be a good candidate for a bioactive setup seeing as they already like to burrow, but it would require some careful attention to a few details. Hognose snakes are pretty temperate species and you wouldn't need to go too heavy on the watering/misting, but some is required for microfauna (sprintails and ispods) to flourish. However your snake will destroy your plants. A hognose is fairly small, which is pretty helpful, but they also burrow so you'd likely need to put any plants in clay pots buried in substrate.
I have no experience with biodude as I (more or less) exclusively use NEherp and glass box tropicals for my vivarium needs except for a few miscellaneous materials. People I have heard from seem to be pleased with his product and indeed I have considered it before, particularly his terra firma/sahara. However two things turned me off from using him:
1. As others have noted, his prices are pretty high. I think there are better deals to be had elsewhere and mixing your own substrate is definitely cheaper.
2. The owner, Josh Halter, used to be associated with a company called "Genesis Exotics" if I remember correctly, and it had pretty poor reviews. I don't know if it dissolved because his partner(s) were shady and the source of the bad reviews or what, but it turned me off from giving them a go.
In regards to drainage layer, you can get away without one if you are very careful with watering, but I would not recommend it. For a burrowing species like a hognose, I would do egg crate with a thick screen firmly attached to it. You want the animal to stop when it hits the drainage layer and not mix things around or shift your screen separator.