Hi Chishower,
Those are great snails, and as Ranchugirl said Shannon has wonderful snails! They always have the nicest shells.
I've gotten snails shipped a few times and they do amazingly well. The orders I got took 3 days for them to be shipped; some were wrapped in paper towels in a container; another breeder put them in bags with water. Either way, they all did well; plopped them in the tank and they were out and about in no time.
To answer some of your questions (to the best of my ability), I personally don't put my snails in with my goldies. They can be a nice snack for some goldies, so I avoid that.
And if you are anything like me, and many other people, then yes, you are in for another addiction. We got our first snail (a cana) and within a year we had hundreds.

I personally like having snail only tanks. It's so much fun to watch them climb all over each other and hitch hike on each other's shells to get a free ride across the tank. They are so much fun to watch grow and are just a lot of fun to watch, overall.
You shouldn't have to get anything special from the pet store. Our snail tank consists of a filter, heater, decorations (we use fake as we have several different species, some of which eat plants), and a hood/light. Ours don't ever slime their way into the filter, yet. But they do have the tendancy to try to crawl their way out of the tank, depending on what type they are. We notice the canas try to crawl out more than the others; luckily they are so huge they don't fit out of the opening in the lid.
One thing I will add is to be sure to feed them foods high in calcium to help promote healthy shell growth. We feed ours snail cookies, which I think Shannon has as well. But they are a mix of veggies, foods, and calcium supplements to help keep them healthy and they absolutely LOVE them.
You should go to www.applesnail.net to learn more about applesnails as this site is like the apple snail bible! And their message board is full of folks who know just about everything is there is to know about these guys.
congrats to you!!!