3-minute video / audio editing

We have a 3-minute video that needs basic editing, adding of music bed at the beginning 45 seconds, and adding of English-voice overdubs to a foreign interview. The places to add the English voices are noted with timestamps in a script. Some stills to be added in to replace existing video footage, in specific places in the video. The English overdub will be at 90% volume while the native voices will still be barely audible at around 10% level. You will need to fade out the native interview answers after letting them run at 100% for about two seconds at the beginning, then drop in the English overdub while the native speech continues at 10% underneath. This style will repeat at the beginning of each section.