Dang, nice work on those ducks!!! Bet those tasted amazing!
Foiling is totally personal preference-- some folks like you do the full meal deal and contour the foil to the Flame Zone pan and poke holes, then foil the covers as well.
Others do like Cliff and just burn it all off in the oven. I personally do kinda half and half... if i'm doing low and slow, I'll just lay a couple sheets of foil down on top of the covers, and peel it off after I'm done. If I'm doing direct grilling, I don't bother foiling the perforated FlameZone drip pan.
As Cliff also mentioned, good airflow is imperative for the grill to operate as it should, so you do need to be mindful of not covering over the holes in the SIDES of the FZ drip pan-- basically you want your foil to go right up to the edge, but not wrap around to block those holes on all four sides.
I will say it IS easier to do cleanup when you do it regularly, rather than letting gunk build up for ages, which can lead to performance issues. Obviously don't have to get it sparkling clean every single time, but... a few minutes after each couple of cooks can save you quite a bit of time in the long run!