Congratulations on your pickups!
I don't have much to add about your original purchasing questions, but did want to say that buying off CL and at shows... You'll want to pick up some PAM (prevent-a-mite) spray and some natural chemistry reptile spray... Mites are really easy for snakes to carry and can spread through your collection quickly. I purchased my first BP at a show a few months ago.. Did not appear to have mites, but sure enough, 2 weeks later I found her soaking in her water bowl. Everyone that I know of advises quarantine, but most also recommend pre-treating a new snake's quarantine setup with PAM and wiping them down with the reptile spray to head off any problems mite-wise. As someone that went through this, I'd really recommend doing this will all new snakes. You have to treat the enclosure bedding with the PAM and it has to be totally dry before putting a snake in it, so I would treat any enclosures you've setup prior to going to the show and bringing home new snakes.
Also, I agree with the others that you will want to see what's at the show... You can look at the vendor list beforehand and I would go to the fauna BOI (board of inquiry) and search for the vendors names.. See what feedback they have whether good or bad, then you'll know if you need to avoid buying from anyone. You can get some good deals at shows.. My first BP is a female pastave that I picked up for $250, not bad for a 2 gene female. That said, I would say you really do need to look for quality animals (pastels that are very yellow not browned out, etc.).. When I went to the last show there were many lower-quality 1-gene animals and it pays to find ones that look really good especially if you can get them for the same price. There are also usually many "flippers" at shows (those that buy from a breeder and then resell) although there isn't inherently anything wrong with these animals, usually they are lower quality and the flipper can't give you as many details on how the snake is feeding-wise, etc. as a real breeder can.
Good luck as you grow your collection!