taking opiates and benzos together is not a good idea. especially because you are obviously naive to opiates. do you even have a benzo tolerance? if not, i would highly recommend NOT doing so.
both drugs produce cns depressant effects on their own. taking them together will heighten this effect. this combination very commonly leads to a fatal overdose.
drinking while on opiates is also frowned upon for the most part. imo, it kills my opiate high and is a total waste. if you HAVE to do it though, let your opiates kick in first, then drink SLOWLY, and don't overdo it. if you're looking to get 'wasted' then do yourself a favor and just drink without the opiates.