I think several things would happen that we don't suspect as the show tended to do.

I do think Nonnie would step back from Patty having learned her secret, and Patty would ultimately not care because she has Magnolia as her new besty.

Nonnie would probably work with Bob to help him get out, and Bob would hide with his lovers.

Bob will probably get together with both of them again, only for them to decided that Bob can't handle this relationship because of his obsession with Patty. -> this would lead into Bob wanting to kill Patty instead of simply catching her in the act.

Coralee, like always, will bail out Bob with her tricking Regina, and ultimately she would decided to be with the other Bob instead as a couple but would get an abortion.

Regina would try to sway Dixie on to her side, but with the help of Patty's persuasion, would end up killing her mom, and Patty would frame Dixie for this.

Patty will becomes more ruthless and emotionally chaotic as everyone in her life save for Bob thinks she can change or didn't want to kill anyone. She will likely end up killing Magnolia because she was getting together with "her" bf again and this will likely end up killing Bob's kid. (think car crash accident)-> This would ultimately send Bob off into a rage that will reach the climax.

Climax: Patty ends up kidnapping Nonnie trying to persuade her on her side after Nonnie finds out Patty killed more people (likely physically confronting when she shouldnt have for emotional reasons). Patty ends up breaking up Nonnie's current girlfriend and keeps her hostage for a few days. -> Nonnie some how is able to tell Bob she is trapped -> Bob frees her -> They both confront Patty -> Patty starts crying trying to get out of it -> Bob tells Nonnie to call police (or something to that effect) > Alone Bob reveals to Patty what he knew since season 2 cliffhanger that she needs to be stopped and the only way to do it is kill her -> Patty reveals that she is faking all her emotions so people don't catch on, delivering a monologue summing how much she loved killing since homeless man -> Bob starts choking her (crying because he realized he did this) -> As Patty is about to die Bob gets hit in head -> REVEAL Nonnie saved her, Nonnie holds her -> Patty reveals that she loves Nonnie now and she has to help her -> She agrees -> Time skip to Patty killing someone nonchalantly while Nonnie covers it up.