O.K.. Here we go.Sure. I'd love to hear your input.
1. One? Good! For balancing reasons, I recommend one martial system only unless the character lacks psionics, magic, or bionics (say, they only have 1 of these 3). If you, say, gave a Blind Warrior Woman Zanji + Ninjitsu. With 7 Martial Art Powers at 3rd level, they would not need the Blind Warrior Woman abilities against Vampires/Gargoyles (as I know them)! Seriously.1. No, only one system. In the book it shows that learning other styles takes years in order to master them, so just one for everyone.
2. Yes. Looking at the Cyber Knight OCC, it mentions that they have a large battery of ISP, which some people would call Chi.
3. I will say no to Chi Combat. I don't know that stuff well enough.
2. O.K.. That Double Existing Chi a.k.a. Double Existing I.S.P. is open to abuse if the PC has that Restore P.P.E. psychic ability. They become one hell of a battery all by themselves. The only drawback is that if they only get x amount of I.S.P. back per hour of meditation. It will take them the better part of a week in some cases to fill back up (unless you House Rule it like I have in Sharseya where 8 hours of rest gets it all back for you). If that's all fine with you, O.K., but please be aware of it.
3. Chi Combat is a heck of a lot of fun amongst those who are familiar with it and play within the spirit of it. Imagine someone knocking out someone else's ability to heal Hit Points/S.D.C.! By ANY means! That's what's at stake - slow and certain death of the character(s)! So, while a lot is at stake, I can't recommend it unless the GM is well-versed in Ninjas & Superspies at minimum (and let's not even get into Mystic China! Wooo!).
Those are my 3 coppers on those subjects. More if you require details! =)
Honor and fun,
Dann =)