>> There isn't an option to buy a pass for HE in the simu store when I log in. I used the filter for Hollow Eve and all I see are Corn Maze passes. Can I not buy a pass anymore?

They're sold in-game now, using SimuCoins you've already purchased. For an Admit 1 you'll need 4500 coins. Then head to the festival area, and you can find invitations on the table where you arrive.

Some instructions:

https://www.play.net/dr/news.asp?id=1679
or
https://elanthipedia.play.net/Category:Hollow_Eve

- I