Can you explain if it's safe to take 2.5 mg lorazepam with 1.5 mg clonazepam plus 150 mg seroquel (quetiapine) xl?

In general, no: I don't know your medical history or what you are already taking, but that is a great deal of benzodiazepine, including one long-acting one (klonopin) and one short-acting one (lorazepam), both in doses significantly higher than recommended initial doses. If this is what your doctor is prescribing, and he knows your history and tolerance, it may be safe. Don't drive until you know how you react.