Based on my stay a year ago:

• Breakfast would always be complimentary, if you choose the breakfast option on check-in (though I wouldn't guarantee they will offer it for more than 2 people). Many of the rates here used to include breakfast though
• There is no lounge, nor any availability of free snacks, around the resort. Note my comment earlier about lounging on the beach - you won't get lots of freebies unlike some resorts
• The kids will have very little to do, as the children's club had limited activities per day, though it did include tshirt painting once a day. The nearby playground may just about keep the 9 year old happy for a bit

I'd heard from a friend of a friend that they booked this resort with kids for two weeks a little after our trip, and were very bored by the end and very unhappy with the children's club. I think a 16 year old wouldn't have anything to do - but it depends on what they prefer, if the ambition there is to sit by the beach and read/play on the internet, that would work out fine. I feel you could do better, though perhaps not within the Marriott brand - I have travelled more and more with children since my original review, and have to say the failing on the children's club is a wasted opportunity, it doesn't take much to run a day of activities (one per hour) when labour is cheap - then allow drop-off/pick-up and set up some more outdoor playing areas.