I've always had a tough time with this type of game interaction... Can Sue be Pulse Waved if she picks the first option of Hide and Seek? (Assuming the Pulse Waver started 4 squares away).

HIDE AND SEEK: FREE: Choose one: Until your next turn, opposing characters can't target Invisible Woman unless they began their turn within 3 squares of her -or- Terrain markers are considered clear for line of fire this turn, if Invisible Women is within 4 squares of them.

Pulse Wave:

Halve range, . Other characters within range can’t use powers or abilities (for this action). Make a range attack targeting all other characters within range and line of fire, including at least 1 opposing character, using printed defense values for each targeted character. If 1+ characters were targeted, each hit character is dealt 1 damage instead.

I'd rule yes, she can be Pulse Waved but I can see an argument for no.

Thanks homies!

Hide and Seek isn't Protected or Safeguard: Pulse wave, so yes, she can be Pulse waved.

To break this down, Pulse Wave looks like this:

1. Halve Range (Replace then Modify)
2. Turn off all powers and abilities within range. (No line of fire needed)
3. Target all other characters within range and line of fire. (At least one opposing character must be targeted)
4. Make a Range attack using printed Defense values.
5. Deal 1 damage to all hit characters.
6. Powers and abilities turn back on.

So you always turn things off before you do any targeting, which means Sue's ability to not be targetable goes away as long as she's within the half range used for Pulse Wave.

Exceptions are:
if the power/ability has "even if this power/ability is lost" or "Protected: Pulse Wave" or any variation of "for the rest of the game", if the character has SAFEGUARD: Pulse Wave, or the power/ability originated from a character that is not within the Pulse Wave range.

Keep in mind Pulse Wave only grants Improved Targeting: Hindering and Characters. Blocking and Elevated terrain will block Line of Fire.

Only for the attack. The turning off of powers and abilities doesn't require line of fire:

This is correct. Doesn't come up often, but it can definitely matter.