Agreed, Better Call Saul's methodical approach to "slow burn" storytelling always pays off and it does so by setting up every piece early one, it's a testament to the writer's attention to detail.
Yes, howard didn't deserve any of the things they did to him, I'm happy that before his life was cut short he was able to call them out for the horrible people they are, Kim was so obssessed with this scheme that she hid the fact they were being watched 24/7 by Mike's guys because Lalo was out there from Jimmy, I imagine that if she had disclosed that info Jimmy would've been too paranoid to go through with their scheme, in the end they both got off on destroying this innocent man's reputation just to get their high, and it resulted in his death, I hope their final interaction with Howard haunts them forever, especially Kim because Lalo may have pulled the trigger but it was Kim and Jimmy who killed him.