Here is my prediction for what happens to Kim, Jimmy, and Lalo:
Episode 8 starts as episode 7 ends with Lalo in Kim and Jimmy's apartment. Lalo doesn't kill them but tells them he needs them for a plot that has to do with Gus. As Lalo is leaving, Kim can't help herself and follows Lalo outside. She has been thinking of him for some time and is drawn to his power and charisma. She whispers to him "if you need anything, anything at all, please don't hesitate." They exchange a look and Lalo goes on his way.
The next episode Jimmy leaves for work and Kim is in the apartment alone. There is a knock at the door. It is Lalo. Kim says nothing. Jump cut to Lalo and Kim making mad, passionate love. They are really, really going at it.
A few nights later Kim and Jimmy are out to dinner when Kim starts feeling itchy. It starts with an itch here and there but within hours she has a brutal, full-body rash. It's on every part of her body. In her mouth, her eyes, everywhere. They go to the hospital where they run some tests. She looks like burn victim at this point. She can't really move or speak. The doctor then tells Jimmy the diagnosis. It's herpes. A really bad case. Jimmy can't believe it. He goes in to ask Kim why she would have herpes. She never had it before and Jimmy doesn't have it. "What happened? Who gave this to you? Who did you sleep with?" Jimmy is confused and angry about being cheated on but his emotions turn to sadness as Kim perishes right in front of him, dead from herpes.
The rest of the series has Jimmy walking around in a daze. He can't believe Kim is gone and can't believe she slept with someone else. Jimmy screws up Lalo's plan he was a part of due to being in a fog about Kim's death. Jimmy's mistakes allow Gus to get the upper hand on Lalo.
In the final episode Jimmy is alone in his apartment looking at a picture of Kim when the candle flickers. In comes Lalo to kill Jimmy for screwing everything up. Jimmy doesn't even care at this point. "Go ahead and just do it. I have nothing to live for anyway." While Lalo is screwing on the silencer he stops for a second and itches his crotch. Jimmy sees this and immediately makes the connection. It was Lalo who gave Kim herpes. Jimmy's resignation turns to rage. He grabs that pineapple-looking top for the anejo bottle and throws it at Lalo's face. "Choke on this you son-of-a-#####!" The bottle top goes right into Lalo's mouth and lodges in his throat. He chokes to death right in front of Jimmy. Jimmy stands over Lalo's body and says the line from the preview, "so after all that, a happy ending." Kim dead from herpes, Lalo chokes on the bottle top and Jimmy begins his life alone as Saul.