On our 2nd boat trip last year, we did a much better job with the bathroom situation which impacted our packing list. We sprayed Poo-Pourri (make sure you get a scent you can tolerate) in the clean water after flushing to seal any smells - do this every time after using the bathroom. Pardon the candor here... For number 2, we sprayed an additional squirt of Poo-Pourri before using the bathroom. When finished, we used a large baby wipe, then rolled it in toilet paper and put it in a large ziplock. We did allow the ziplock to fill some before throwing it out since it was just our immediate family - and the wipes ensured that there was no smell when opening and closing the bag. Of course, if it starts to smell, get a new bag. On our 1st boat trip, we flushed toilet paper and did not effectively use Poo-Pourri. Of course, our ignorance resulted in a smelly boat and a septic system that never worked effectively on the trip. We are lucky that we didn't clog the system. With our new method and proper emptying of the holding tanks on the 2nd trip, we never had an issue with bathroom smells.

We also take an audio cable to plug our phones into the boat's stereo. Since we have 12 and 14 year old girls, I take a ski rope for pulling them on a paddleboard behind the dinghy. This also allows you to disconnect the handle and tie it to the bar on the dinghy davit for swinging off the back (if the boat has this - we are on a powercat). Otherwise, it seems that you have a good list.