Focus on Inara last, aim for everyone else first. When needed, poison her and get a couple hits in, but make sure to move around so she has a hard time hitting you because her shooting time is slow.
If he has his shield larger with his talent, try to stay on the side they are on without them knowing. This makes it easy to hit them because his shield only stops attacks from the front. (if you are a tank, keep pushing them back past it to hit 'em)