Hi...i have some answers 
1 & 2) you can keep 1 leo in a 10 gallon
3) they are pretty easy to care for
4) you need 1 warm end, 1 cool end. warm ends needs a humid hide, cool end needs a cool hide - warm side needs to have an under tank heater, you also need a day light and a night light, a temp gauge - shallow water dish, mealie dish unless you plan 2 keep crickets, and a calcium dish. dust your feeders before you feed them. feed babies everyday, feed adults every other day. - change the water everyday - hand tame your leo by handling it up to 15 mins every other day
5) they eat mealworms, superworms, and crickets for their staple diet and a wax worm can be given as a treat every other week. they prefer live foods because they like to "stalk and attack" them.
6) they can go up to 12" in length
i may have missed some, so you might want to visit a Leopard Gecko care sheet. I am also a newbie at leos, but before I bought one, I did research for about a month by reading through people's posts on this site and reading through leopard gecko care sheets. there's a leo care sheet on this page and one that i seem to remember the most (because it's an easy URL 2 remember) is http://leo-land.net . easy searches can be done using GOOGLE.com
ok! have fun N good luck with your leo! 
[aimee]
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1.0 Albino Leopard Gecko (Melvin)
1.0 Black Lab / Pitbull mix (Mikey)
1.0 Blue Fighting Fish (Blue Balls)