The 16th and 18th are booked heavily with very expensive room rates (a wedding could be taking place----with huge family and friends). I checked, and the 17th has a 2000 pts + $35 USD rate, you could call SPG and negotiate only that day. I think $65.00 + the points at this hotel is a good deal during the on-peak Xmas/Wedding season. You could always stay at The Comfort Inn for the same rate.

As for transportation from KIX, you take the Nankai Limited Express train (not the JR Line) to Namba station. There is more comfortable "(Sigma Sign) Super-Express" Nankai train for 500 yen extra, but that still makes stops. But from Namba you have to go for a real long underground walk to transfer to the Kintestu Line for two more stops (operated by another train company).

I believe for 400 yen more, take the comfy Bus to the Sheraton Miyako. At KIX, you want to go to Bus Stop Number 7, that goes to Kintetsu UenoMachi Station which is below the hotel.

Be nice, polite, think like a Japanese and you'll be treated well at this Sheraton.

P.S.: I went in the hotel more times than I can count with a huge box, backpack, and suitcase, and the staff knows right away if you need help or if you don't. This is a business hotel.