If you want a delayed teleport use a trigger_multiple. Just set it to activate the teleport trigger after a delay of x seconds, for a onstarttouch with !activator as the entity. Then have it deactivate the teleport again after a slightly longer delay.
As for landing on it twice, there is probably some solution using a logic system, such as a math counter to count how many times a player has entered a zone, again using something like a trigger_multiple sending an output to a mathcounter, and when the counter reaches the # times you want (ie 2) it activates the teleport. However, you're going to run into problems if 2 or more players are on the same jump and I can't think off the top of my head how to make a separate counter for every player.
As far as I know you can't do that with the lighting. Maybe just have a high ambient value or something and lots of bland lighting in that area so there's no shadows etc.