Creating an Allied NPC? (for Zenith's TB system)

[Maus]

I have three questions concerning Zenith's battle system:

1. Is there any way that I could create a friendly NPC in battle- such as reinforcement troops or friendly fighters that come to aid the party, without having to create an extra party member (and thus have to bother with hiding the person every time I call for a party switch)?
   
2. How do I switch it being controlable and being handled by the AI? (or is it even possible?)
   
3. Once that NPC is created, how do I set it so that the battle ends in failure if its hit points reach 0? (Ideal for protect missions)

I'd greatly appreciate your help!