#1
Shoot a bullet in the air medium range from zombies
Run away from the location
Start spraying a full mag in the air
Those zombies alerted to the first bullet most likely won't chase after you (can be random)

#2: Aggro on a zombie, run away , go into building, wait for how long he takes to come inside

#3: this one is tricky, and I only got once to be done, but...
Get a zombie near one of the hangar hills
Shoot bullets in the air, whlist on top of the hangar hill (while zombie is on the ground, not on hill)
Check if he aggros and chases onto hill.

If not, check if he will chase once you step down off the hill, and shoot

#4(last one), Get a infected aggro or just roaming, to navigate across one of these hangars hills, and check if he morphs through the terrain and gets stuck inside the hill

sorry if this is very unclear, but the state of zombies right now is very unconsistent/buggy. Let me know if you guys need more info, i'll try to get some.

*also forgot to mention, they sometime crawl away straight endlessly, regardless of humans being near, or attempting to aggro (crawling in a crouch position away, or crawling prone away in a straight line)