SC2Mapster

Just check out my demo maps for some inspiration (the ones that still work).

1) Use an Effect - Target ability, make sure the Auto Cast flag under Stats: Flags is enabled and the various fields beginning with autocast are set to your liking. Under what conditions is it to do x/y/z? I say have a simple Launch Missile effect that does like the marauder with a Set effect on impact that does a Damage effect and an Apply Behavior effect that applies a Buff behaviour that does the slowing. Use an Action actor creation when the Launch Missile effect is used for the visuals else just give the Missile actor itself the wanted visual.

2) The Action actor creates a Model type actor using the Combat: Impact Model field. Alter the actor events of that actor or make a new one and link to that. Use either a Set Tint Color or Texture Select By ID event action (for the second one refer to the tutorial in my signature).

3) Use a Model type actor with a retextured splat model like the zergaoecursor. For the visuals on the targets do like the zerg fungal growth and have a Model type actor created on the target when the aura target behaviour is applied.

4) Have a Model type actor created at a high z offset (preferably around the target using a SOp Random Point In Sphere SOp) that has a Site type actor hosted on it. Then set the Combat: Launch Site field of the Action actor to this site. Else look at the raining cows tutorial.

For the second part just for the like templar shadows. Yes there is a tutorial on it. Just give the Missile actor a looping timer under events that creates a Model actor with a timed duration (also events).

5) For that use as in number 4 but have the missile mover use a Throw driver going -ve z.

At least you are trying to better yourself since the arcade (at least in Europe) has a pretty low standard.