Hi There, Robin,
1. Yes bonsai soil would do well in pot sizes up to 1 gallon for small trees. If you go larger, you can get into a growing box (see Tips & Techniques board for the article on growing boxes)
2) It's "metal halide" but we knew what you meant
The type of light (incandescent, flourescent and metal halide) wattage of the light, the distance to the plant and the number of hours each day all add up to a certain amount of energy.
You want the lamp pretty close to the tree, but those metal halide lights are bright, but they can get pretty warm. Light intensity drops off as the square of the distance, so the distance makes a big difference. So you want to be as close to the lamp as you can without burning foliage.
Jerry Meislik has an article over at www.bonsaienthusiast.com in the subscription section that's a good read, but it's available only as part of the $20/year subscription.
I can tell you he recommends starting out at 10 hours a day and working up from there if you're limited by lamp intensity or distance.
3) The tree would do quite well outdoors (probably better) in most areas. Trees appreciate a lot of ventilation.
Regards,
Matt