thanks for everyone's thoughts...
I just called Guest Services at Beach Club and was informed that I could check-in anytime that day (and when I asked specifically if I could check-in any time after midnight, she said "well, yes, you can"). I understand that you talk to different CMs at different times and you can get different answers, but this info., along with those of you who have mentioned that you have checked in at 6 and 7 am, has helped me at least tentatively plan our day.
(as i mentioned, i don't need the room itself until normal check-in time).
have a good night!