Agree with you on the dumping in public. AIUI, the cartel is, well, gunshy about killing in the US. Isolated notorious examples aside. (E.g., the hit on a cartel lawyer/financier in an upscale shopping center in a Dallas Fort Worth suburb: https://www.nbcdfw.com/news/local/Murdered-Southlake-Man-Headed-Major-Mexican-Drug-Cartel-Attorney-Says-374504041.html) See also, the difference in murder rates between Juarez and El Paso, or any two twinned Mexican/U.S. border towns really.
If they didn’t want to hire the pozole guy, and his procedure doesn’t look all that hard, then backhoe a nice hole somewhere and dump. Or do what the House of Death did for their victims. What that is, I don’t know, but I imagine an antelope hunter will find something grisly near Fort Bliss or the Hueco Tanks, one of these days.
Borderland Beat (http://www.borderlandbeat.com/) is a great resource for news like this, and if you find yourself currently plagued with easy, dreamless sleep.