I suppose, Friendships are at an end. MK11 made them over and done with, unless characters that weren't in MK11 are still yet to do this finisher. Bring on Suicidalities for MK12, because thing is, in MKD they wasn't all real Harakiri.

Rain - Surfing a tsunami.

(Would need special camera angles)

Motaro - Charging with rage, at a red cape. Like matador bullfighting, with the challenger using the muleta.

(Would need special camera angles)

Kobra - Snake charming, hypnotizing a cobra into a dance, out of a basket. Opponent or Kobra could use the pungi.

Fujin - Takes off in an air balloon, blowing warmed wind into the envelope bag, while waving.

(Would need special camera angles)

Bo' Rai Cho - Toasts, then puts on a beer helmet with straws. Guzzles all of it speedily. Then poses, before collapsing intoxicated.

(He's more a high-class wine drinker)

(He's not in MK) Wu Lae - Peels of tangerine skin, then munches it. Then there's a food fight, with satsumas and oranges. Finally he gets a juicer, pours the juice into a plastic mini water pistol, and continues to shoot the opponent with it.

(Different from Rain)

Noob Saibot - Studies the floor, dusting it off. Draws for an oil well tool to drill the ground. After, he rapidly uses his scythe to dig for petroleum fuel from under the surface. The ground bursts and erupts, then he starts skipping in circles joyfully in the sprinkling oil fountain.

Shao Kahn - Relaxes and lies down on a fancy cushion. Opponent nods, then slaves hand feed him grapes.

Scorpion - Puts on cowboy hat and cracks whip, then swings and launches lasso and throws cowboy rope hoop around opponent.

Stryker - Shooting range appears with a MK dragon logo on the paper sheet, as the target. He then proceeds to put on ear protection and shoot out the shape of the MK logo. Afterwards he blows the smoke off his 9mm pistol in a chilled way, then spins his gun and puts it in his pocket strap, bringing the silhouette back while looking proud.

Smoke - Presents opponent with a bong then they toke until the cranium explodes, with blood and smoke coming out. Smoke then holds up the No Smoking sign.

(More like a Fatality but it could work for a Friendship)