EMH are included to all on site guests who purchase tickets to enter the appropriate park. I believe you must have your KTTWC available at the time the EMH begin.
My understanding is that any Disney Resort guest can take advantage of EMH, regardless of which resort they are staying at, as long as they have a valid theme park ticket on the day/night in question.
What gets you access to EMH is being a registered guest at a Disney resort. Every registered guest gets it, regardless of how they paid for the room (DVC points, cash), or what kind of pass they have. Same goes for all the other onsite perks, like free parking at theme parks, charging to the room, Magical Express, etc.
I should also clarify that just being a member does not get you these perks. So, if you were staying offsite for some reason, you don't get access to EMH. You have to be a guest at a Disney resort.
Yes as PP'ers have said it is for all onsite guests. They will ask to see your KTTW card before entering an attraction, they won't ask to see your park ticket in addition to that.