This list is a good start. I would recommend going ahead and getting all of your equipment before you get your snake. That way you can get it all set up, run it hot, adjust your temps, monitor your humidity, learn the ins and outs of your thermostat, etc, before having to worry about actually having a live animal in the enclosure. You'll be happy you did. If you wait until you have the snake, you'll be rushed to figure it all out, and you (and your snake) work both be stressed out over the adjustments and tweaks that will need to be made... And there WILL be adjustments and tweaks to be made.

Also, I noticed that you put rats on your list. (You also mentioned getting a baby BP, so maybe mice instead of rats). You didn't specify live or frozen, but if you're planning on live, be sure you have storage for those ready also (including food, water bottles, etc). If you're planning on frozen, be sure you read up on proper thawing. I like your heat gun; I own the same one. It can be useful when checking temps during thawing, but do not rely on it completely, as it will only measure the surface of your rodent, and the center being thawed correctly is paramount.

In general, it sounds like you've got a pretty complete shopping list, and I commend you for doing the research in advance. But again, I strongly urge you to go ahead and get the enclosure set up and warm, and run it for a few days before you get your snake.

Good luck, and keep us posted!