4) Spawn Ordering does not effect Spawn Points or Spawn Zones (however, it plays a major role in the Spawn Areas used in Invasion).
Using only Weak and Anti zones together can never have an effect greater than one single Weak or Anti zone. They DO cancel each other out though.
Weak + Anti = 0
Weak + Weak = Weak
Anti + Anti = Anti
there is already a strong zone in the same area. Then they combine as you would expect:
Strong + Weak > Strong
Strong + Weak + Weak > Strong + Weak
Strong + Anti < Strong
Strong + Anti + Anti < Strong + Anti
And finally, two strong zones don't ever combine.
Weak/Anti Respawn Zone<Enemy* **
Enemy* **<Dead Teammate/Self
Dead Teammate/Self<<<<Respawn Zone
*Stacks per instance
**Varies Per Weapon and L.o.S.
As explained by Bungie, if you place a Safe Zone, any time a player is outside of it, they will die, or begin their timer, and if a Kill Zone is placed inside a Safe Zone, it will take precedence. Best practice is to use Soft Safe Zones (with a countdown) to define the playable areas, Soft Kill Zones to denote areas where you would rather players not go/camp, such as roof tops, and Hard Kill Zones so that players die when they fall off the map (think The Cage). Using Hard Safe Zones tends to lead to too many problems and many Jetpackers dying seemingly randomly for poking their head out of your proposed "ceiling". You also want to take into consideration that using a Hard Safe Zone coupled with Soft Zones is essentially the same as using Hard Safe Zones alone; as soon as you leave, you will die, no countdown, which is yet another argument to avoid Hard Safe Zones unless you have a very specific application.
Shows a view of the map during the choosing of