Any time one has both substances (cocaine and alcohol) in their system at the same time, they’re likely to create some cocaethylene. So both the scenarios you describe would likely result in its formation.
And given the fact that cocaethylene is significantly more cardiotoxic than cocaine, both scenarios should be avoided if one has a low tolerance for sudden cardiac death. Early defibrillation is the treatment of choice for such sudden cardiac death, but even having an implanted defibrillator in situ does not completely guarantee successful resuscitation.
If one must consume both, I’d recommend at least 24 hours of alcohol abstinence before ingesting cocaine. Longer abstinence would be recommended if liver dysfunction, such as cirrhosis, is present. Like permanent abstinence.