Hello game mechanic junkies! (This is the place for game mechanic junkying, isn't it? At least, it always seems to be in the cheats, hints, and spoilers section whenever I see such a thread.)

I have some questions about the frost projectile combined with additional spell effects. I did a quick Google search, and if I don't get a response here I'm going to test all this tonight (and post the results, if anyone's interested), but in the meantime I thought I'd see if anyone else has tested this. So, here are my questions!

1) Duration! I originally thought the frost projectile would stick around through the whole spell duration, but when I checked the UESP, it sounds like all frost projectiles persist for the same amount of time regardless of the spell duration. Just looking for confirmation on this.

2) The real question -- triggering other effects! Say I want to have some fire damage ride along with my projectile. So I make a spell like this:

50 frost damage in 20 ft for 2 sec on target.
25 fire damage for 2 sec on target.

I toss this at a group of enemies. Do they all get hit with the fire damage? Do the enemies on the edge only take frost damage, while only enemies who take a direct hit receive fire damage? In order to deal fire damage to all enemies, does the fire damage also require an area of 20 ft?

If no one knows, I plan to experiment with it on a frost atronach tonight. But I figured it wouldn't hurt to see if anyone else happens to know off-hand.

Thanks!