You weren't exactly clear as to which resort in Negril you are looking into. If it is Couples Negril (and not Swept Away), then yes, all rooms have mini-bars.
Age is not an issue at any of the Couples resorts. I wouldn't be concerned with that.
I would suggest getting a standard garden view room. You aren't in the room that much and if it means you could stay a few extra days, I'd do that over upgrading. The rooms really are all the same with the exception of the suites. The only difference if the building or floor.
Juliann & Jeff
Jamaica Soon Come