Natalie,
Welcome and I'm sorry I spaced on welcoming you sooner! I'll try to answer as many questions as I can, I think the other ladies can add in more info. Ann has lots of details. Here is what I know:
I don't think you can start earlier but if you find out otherwise let me know, I would like that too. I'm pretty sure dinner cannot be on the beach because they set up the dancefloor/reception stuff there while you are eating dinner above. There are several hammocks everywhere, some covered and out of the way. Do you think his grandfather could work with a hammock and a blanket? They seem pretty strict on the no bridal suite after dark. Perhaps you can arrange a separate boat to take him back sooner? I know they have smaller boats the staff use to get back and forth. Someone here used their photographer and was pleased, let me remember or look it up. Sorry that's all I know, Nicole is very nice and informative so don't hesitate to contact her directly too if we can't help you with something.
Best Wishes,
Jamy