First, congrats on the Royal Suite, you're going to have an amazing experience. Most of your questions have been expertly answered already I see. I will add that Luminae is also available just for suite guests and I generally enjoy their lunches more than many of their dinner options. Ok, mainly I go for the specialty burger they offer at lunch! :)
I don't remember there being a bar you can sit at in the retreat sundeck, as I would have certainly done so if that was an option, but they were very quick with drink orders. They likely have a bar setup just inside they utilize. There is plenty of room up there and great views.
I'd also reiterate that you should tell the shoreside concierge about the birthday celebration. They will usually do something fun for you that day.