Things may have changed since I leased. My lease experience was a seven-passenger car. I'd say a van will be much more suitable for your family. The car was perfect for our family of five but would have been too small if we were bigger or carried more luggage.
When I leased pick up and drop off in France was free. Pick up/Drop off charges outside of France were reasonable - significantly less than dropping a rental in a different country. I picked up in A'dam and dropped in Rome.
Full CDW is included in the price, you don't get a choice to use other insurance.
The term of the lease has to be (or had to be, there may have been changes) no more than six months. You have to order it from outside the country and be a foreign person traveling on a visa. Peugeot and Renault were the only options, I believe they still are. I went with a Renault only because of the model of car I chose.
Pick up worked great. An agent picked us up at Schiphol, drove us to a dealer and processed the paperwork. It was reasonably efficient. Drop off was in Rome at the airport (the one with the train, I always get them mixed up). The agent wasn't there for our appointed time. We asked around, another rental agent called him and we waited more than an hour for him to show up (Ah, Italy!). Fortunately, we were dropping at the beginning of our stay in Rome so we weren't pressed to catch a flight.
Rental seems to be the better option when you only want a small economy car (and use your credit card insurance). Prices for rentals go up drastically as you get away from small cars. I think you'll find leasing is a good option for a van.