Hello,
Good for you on doing your homework before bringing home a beardie!
I'm sure you will give your new guy a great home when the time comes. To answer a few of your questions (I will try my best, please correct me if i am wrong, anyone
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Astroturf is fine. Not sure how hard or easy it would be to clean though.
Personally, I would only keep one beardie per enclosure. From what I've been told (i only have one, and have only ever had one), they are happier by themselves. Two males cant be put together, a male and female will breed, and two females may or may not occasionally get into small fights. Of course I have no experience with keeping two at once, I am just going by what I am told 
To get a beardie with a good personality, its good to get one from a good breeder, and get it as a baby, so that you can watch it grow and let it learn to love you! Most babies are jumpy at first though, but they get used to you quick with proper handling. Most beardies are pretty mellow so its easy to keep them tame. I actually got mine from a small petshop, but its was a very good, clean little place with proper husbandry.
Yep, you still should give them calcium and D3. the UVB bulb helps them process it. so you should have both.
Will you have a basking bulb as well? I know you mentioned the heat tape, but its best to have an overhead incandescent basking bulb, since they should have the overhead heat.
Hope this helps! 
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~Melissa~
1.3 Leopard geckos (Guido, Oasis, Gypsy, Marli)
1.0 Bearded dragon (Pharoah)
1.0 Hog Island Boa (Michelangelo)
0.0.1 Crested Gecko (Picasso)
1.0 Ferret (da Vinci)
0.1 Chinchilla (Eevie)
1.0 Chinese Praying Mantis (Sid)
Melissas Menagerie