I got none of those defects except maybe no.4. I took it off and tried to put it back in but for the life of me, can't understand why it won't go in all the way, leaving a big gap. I pushed the radome all the way down, and apparently that was causing the nose cone not to enter properly , if the radome is in its normal position. Maybe you can try that.
Its probably due to imperfections of the nose cone mould cause when i see the inside of the nose cone, the plastic looks a tad warped. As in not perfect.
Mowe:
I hoped Yamato could've put a ball joint on the VF-0's head so it can do that head pose without moving the neck plate.