I prefer the Tambu lounge drinks too, camcolt.
As for the Lapu lapu problem, lol, I go to the lounge to get one in the pineapple, then order the next drink at the pool bar and refill my pineapple that way. One of the bartenders (at Tambu) told me they are really "mai-tai's" and to order those instead--they're cheaper without the pineapple. So, get one pineapple, then refill with mai-tais.
In fact, this is one of the reasons I dislike the pool bar. I have had rude bartenders several times, really poor service, and they sent me up to the lounge for lapu lapus--instead of just telling me that they could make a maitai without the pineapple! I would not assume you can get a maitai there, I would check with the bartender.
I hope I get to meet the famous rosie next time, because the other bartenders have all sucked.
Oh, and dh has bought single beers from the store on the second floor to take back to the room. There is also wine, and champagne, and bottles of liquor (you would have to mix your own drinks though), and perhaps purchase glasses for those....?