1. You’re building a hog smoker? Haven’t seen a vertical hog smoker before. I think horizontal is the way you want to go. For fuel, I like the cookers that have a pull out coal tray that puts the right under the pig. Helps crisp up the skin.
2. Barrel hinges work great. Otherwise just about every build on here has an example of homemade or prefab hinges. You can also see a lot of good examples of how people seal their doors - outside or inside door flanges which gaskets to seal up tight.
With a mig, plasma and an angle grinder, there’s just about nothing you can’t build. Post your questions, i guarantee someone has experience with it and can help you out.
Good luck with the build!