In order of severity, these are the worst.

I think you'd rather report these at the WarThunderVehicleLibrary page, from which this mod takes all of it's flight logic. Though apart from the vision issues (#4 and #5) these bugs were present in the *original* version of the code, which has been copied wholesale from either the UH-60 blackhawk mod, or a previous mod.
I had taken a look at the UH60 mod's code back in B41 to fix some bugs that are most noticeable at very low FPS (worst case would teleport you way outside the map area, where you would get irrevocably stuck) and did so again when the code resurfaced for B42 in that library mod...
I had also rewritten parts of the code responsible for handling input and controlling the heli, since that also had some issues... my version is much smoother, again, especially at low FPS...

For now, that stuff only exists in my private copy, since i am not yet familiar with modding PZ from scratch... might look into that in the future...

#4 and #5 are likely bugs introduced by the vision and lighting rework in B42, more specifically one of the patches since it's release. i am 99% sure that i was able to fly around in the initial patch without the zombies on the ground disappearing. neither did the shadows stick around like they do now...

From poking around in some disassembled java classes from the PZ game directory (for some unrelated work as a potential mod commission for someone), i have found some potential explanations for the vision bug though... essentially, the lower elevations are not fully re-rendered anymore once the heli ascends... likely a bug with the newest patches, that is also responsible for the entire world outside of a skyscraper blacking out once you are high enough...