Headscratchers / Dengeki Stryker

• In the Zero saga, why wasn't Sayaka dissapearing while all the other fictional characters were?
  • The Steel Saga explains that she slept through most of that.
• Why doesn't Yamato recognize the Balborans outside of combat?
• Okay, it's heavily implied that the fictional world of the Dengeki Stryker manga is far more primitive than the "real world." And yet, its advanced enough for its governments to produce groundbreaking cybernetics. What's up with that?
• Why does the breach in Yamato's contract cause Yamato to fade from existence even though he himself technically isn't a Dengeki Stryker character? It would make more sense for Yamato to simply lose his powers and false memories as Stryker Zero.
• Why does Mirror turn into a monster?