5 days will be enough for you to see Hong Kong and Macau. The ferries between these two cities will be in service 24 hours around the clock, so you don't have to stay one night in Macau. It is usually for travelers to get to Macau in the early morning and return to Hong Kong before night.

As for the tour itinerary, I think you could select some interesting attractions and refer to others' travel reviews. On the other hand, you may have a look at this website's recommendation on Hong Kong tour. It will be a long time before your coming, so you could prepare everything well.