That's my usual method with gelatin in a beer that needs dry hops. There's been much discussion on HBT about this, but you'll probably find you get more aroma from dry hops when the beer is warmer than serving temp.
If the dry hops are suspended in a mesh bag (unwaxed/unflavored floss works great), you can always pull the bag out after the keg is chilled and right before adding the finings. I'm not sure about biofine, but gelatin definitely works best with cold beer.
So dry hop for the desired time, chill, pull the bag, add finings, wait 4-5 days, push out the first murky pint, and carbonate as usual.