Hi Emily,
Not sure if you still come to this thread. I only just saw it. Are you also requesting for photo highlights too or only just video highlights?
I agree the videographer needs time to do the express video highlights properly. It must be matched with the right music to create the right atmosphere, so its not an easy job.
Perhaps you can consider letting the videographer off to do his highlights, and just keep the photographer (very common for them to limit their shooting time to 1pm for the morning, you may have to pay extra for them to stay extra hour) to take pics of you with your family... provided you didn't ask for photo highlights as well.
I also think its best to communicate to them your needs now, rather than leave it till you come back from Singapore (and find that they can't do it, and there is no room for negotiation coz its too late?)
My videographer Sim works with a partner. His partner Ken comes in the morning to take the video shots. Sim comes at 1pm and takes the material for editing. When I told him that I have not decided if I will have a church wedding, he said that from his experience church weddings always drag on till about 3pm, and there is not much time to do a good job in express highlights. Perhaps you can find out if your videographer works in twos, then one can leave at 1pm to edit the morning footage while the other stays to capture the afternoon events. Or, as my videographer suggests, you may have to consider playing your highlights a bit later (eg 9pm) so they will still have time to do a proper job. You really don't want them to rush through it.
Good luck!