GMing for my teen buddys, First time GM needs advice for GMing high/middleschoolers Options

[Lok1 :)]

Yo chummers, some of you know me some of you arn't that lucky yet regardless I post hear requesting your advice in any form that you may have it.
I've convinced some of my chums that I normally hang out and play D&D and its reletives with to give shadowrun a try. They already know my GMing style but none have any experince outside the realm of d20 an a few have hardly any rollplaying experince. I have a few quistions hear that I would like to see your take on. But feel free to ingore theise and give other advice that you think might help.
1. What modules would be good? I'm thinking either foodfight followed up by a modified version of running wild but am open. (I hear knasser has some good stuff)
2. One of the players is a major marine buff, and wants to play a ex-military marine like character, how can I accomidate this?
3. Is thier a "idiots guide to the matrix" write up. I understand (or think I do) the matrix very well and my primary PC is a decker. But I have a hard time explaneing it especial because the 4th ed matrix is diffrent from what I learned and most of my knowledge comes from SR fiction that I've read. One of the players wants to play a hacker.
4. What are some ways to streamline combat to keep it fun?
5. Do you think I should run the game any diffrent for a group partialy consisting of middleschooers. (This is a bit hypocritical seeing I started playing as a middleschooler)