Depending on where you stay in Gouda, most of these trips are train only (the trips between Gouda and Schiphol (Amsterdam Airport), Den Bosch, Utrecht, Delft, Amsterdam). Depending on where you stay in Amsterdam, you can either take a train or a bus to Schiphol.
There is not really a transportation pass that would give a discount. You could buy three "ov-chipkaart" at 7.50 euros per card (dont buy one for the 11 year old), but that will in this case not give you any discount.
For the 11 year old: Buy for the train trips a Railrunner ticket. This will cost 2.50 euros for a day. https://www.ns.nl/producten/en/meest-gekocht/p/railrunner
The 17 yo pays full price. Buy the full price train tickets at the station from the ticket machines or buy them online at https://www.ns.nl/producten/en/meest-gekocht/p/retour. The online ticket is the same price as using an ov-chipkaart. Tickets bought from a ticket machine have an extra fee of 1 euro. (does not apply to the Railrunner ticket)
Your trip to Lisse, will be, I assume, to the Keukenhof. From Gouda that would be a train to Leiden (via Alphen aan den Rijn or via Den Haag Centraal) and than bus 854. If you have not already bought the Keukenhof tickets, you can buy combitickets, including the bus on https://keukenhof.nl/en/ov/ . If you already bought tickets without the bus, buy a day ticket at the OV ticket shop in Leiden.
Day Ticket There are Day Tickets for sale for all Keukenhof Express buses for €11.50 (except Bus 852: €16). These Day Tickets are €7.50 for children aged 4 – 11. These Day Ticket(s) or dagkaart(en) are only available from the OV [public transport] ticket shop.
source: same page on Keukenhof site
plan your train trip via ns.nl/en and you train/bus trip via 9292.nl/en. Note that train tickets are not tied to a specific train, but are valid for the entire day (til 04:00 the next morning)