You do get your originals back of your certificates. Since we left the day after on a Sunday when the office was closed, they were given back to my parents so if you aren't staying you may want to arrange how to get them back.
For private functions you can allow time in between for pictures. Functions are 4 generally 4 hours unless you want it shorter, over 4 hours you have to pay extra. You can definitely have time in between for pictures, generally your coordinator will recommend it. To book your private functions you can do it 3-4 months in advance. If you are booking hair appts for bridesmaids or other guests, they will need to have booked already and you will need their booking confirmation number.
They say gratuity is included b/c it's all inclusive but when you see how hard the people are working at your events, you will want to tip them. I would plan at least $20 for the bartender at any private function, $20 for the personal server assigned to the bride and groom for the private event, $20 for the sound tech, at least $50 for the WC and $20 for her assistant. I did not tip the priest which was probably a faux pas however, he did not come to our rehearsal so we had no idea what was going on during the ceremony and he made us take a picture with him before the ceremony ended so he could leave as fast as possible after the ceremony so I guess I didn't feel it was warranted. I would recommend just having extra tip money on you as we didn't realize some of the people we would want to tip and ended up having to borrow money to make sure everyone was covered. Also the wedding office was not open on Sunday morning so make sure you tip your WC that night or prior too if you are leaving the day after.