Ive been meaning to do this, so here it is!
(If i swear, sorry but that's my way of describing! Sorry!)

I have found an easy technique to the UnwantedGuests!
"if your not very tough or don't have a lot of health, all of this is easier in a group"

If you are a member and have a ride, hop on it to get to the gate... the only people who will attack you on the way there are the three ninjas, and those are easy. Now go in the door!

Start off on the same path you took with Past Kai:
Run down to the ditch killing everything you see! Even though Orchid is off to your left, IGNORE HER!
Run down to the tentacles and use your power attack! (if you have a "blast" like some form of explosion that comes out from you, stand between them, if you have a "burst" that flies in front of you, stand in from of them both.) Now unleash holy ****!
Once you kill him, go back to where you saw Orchid. Even with her attacking you, ignore her. Just go right after the pearls. She will say something and run out the door.

TADA! ive found that to be easier for some reason. BuT ThAtS JuSt mE!!!