I dont have Raiden and Shujinkos, I have Bo rai cho, but I found it out of the blue and I dont remember how to get it but the others are here:
Li Mei:In the Blue-town in Order Realm, Find her and fight her.
Mileena: In Earthrealm (F-7) be there between 7pm-9pm
Kabal:In Chaos realm (b-1) Find him and fight him
Nightwolf: In the Netherealm(A-4), I think u have to find him n fight him
Tanya: In Outworld(c-2) Find her and fight her

i found nightwolf but it keeps saying why did you attack me
how do i get him to fight me?'
so i can unlock the the outfit

I'm still trying to find Rayden's alt outfit, they say in Edenia F-3 you will see rayden in his black outfit, fight him and win,and you get the alt. outfit.but in Edenia there is no area F-3? theres F-4,5,6,ect but it skips F-3? would anyone know whats in F-3 or near it to make it easier to find?

Raiden
go north from the portal in edenia go into the building area go right till you hit the grassy tree area then go south that will take you to the front of the building area with water running cross the bridge and fight raiden by the fountain.
Tanya
In Outworld go to the north west sectin find tanya and do her quest then leave realm come back and she will be at c-2 fight her and get her's
Nightwolf
Nightwolf: In the Netherealm(A-4), (first do his quest the creature that stole the totem is right behind you on the onther side of the bridge then you hit him and take it back take it to wolf and then fight him.)
Li Mei
in orderworld she is in the bluse section to the west walking around , Find her and fight her.
Shujinko
F1/Edenia - 3:30-4am (inside building) 3:30-4am on tuesday
Mileena
Koffin HL - F-7/Earthrealm (7pm-9pm)
Boï Rai Cho
Koffin IB - 2086 Onyx Koins.

Thank you.

No problem i try to be as descriptive as possible i wish other's would.