So, we are a Harm Reduction outfit and I can't do anything terribly irresponsible, but this is my opinion. You are taking Benzodiazepines regularly, you're going to take Morphine and then drink Alcohol, yes, bad things could happen, but it would be a fluke for this very combination to kill outright a healthy individual.
You are most likely looking at nodding out and starting at your shoes, but it shouldn't be dangerous in the true sense of the word. This is only, and I mean, only if you are only having as you say, 3-4 drinks. You are not getting drunk, maybe popping an extra Alprazolam at bedtime, that sort of shit. I can give you my blessing through my experiences and knowledge that this isn't in the realm of "utterly fucked up", but you're getting ready to be called up to the Major Leagues from the Farm Team at this point. You're right on the cusp.
If you need any more advice. You know who to call. Ghostbusters.